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Millionaire's Shortbread

Juliane Grasekamp author bio picture - founder of Bonni Bakery dessert recipe blog.
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Millionaire's Shortbread is a classic Scottish treat consisting of layers of buttery shortbread, homemade caramel, and a rich chocolate topping. 

Three pieces of millionaire's shortbread in a stack, the middle one has a bite taken out of it to show the gooey caramel filling.

This Millionaire's shortbread recipe always sold out quickly in my bakery. I've tested countless versions of it, and this one consistently delivers. I use a slightly different method than most recipes that makes the caramel layer smooth and rich with just the right amount of chew. It's a simple tweak that brings out a deeper, more developed flavor and helps the caramel set up beautifully without becoming grainy or brittle.

Millionaire Shortbread might be the new 'it girl' on North American baking blogs, but in Scotland? She's an old-school icon. These days, you'll see all sorts of remix versions - like ganache instead of proper chocolate (please don't do this). But if you're here for the real deal - authentic Scottish shortbread, chewy homemade caramel, and a crisp chocolate top that actually snaps when you slice it - this is the one. No fluff, no weird substitutions, just the classic in all its indulgent glory, with a detailed recipe to help you nail it first time. 

Jump to:

Why This Is The Best Millionaire's Shortbread

  • Authentic Scottish shortbread recipe to make a perfect buttery base.
  • Two-step technique for the caramel that makes a smoother, more reliable caramel with deep flavor.
  • Detailed, science-backed instructions to help you make the perfect millionaire's shortbread.

What Is Millionaire Shortbread?

Millionaire's Shortbread is a classic Scottish treat consisting of three distinct layers - a buttery shortbread base, a thick layer of soft caramel, and a delicious chocolate topping.

It gets its name because it is so incredibly rich, though they are often also called caramel squares, caramel shortbread, or caramel slice.

Ingredients for Millionaire's Shortbread

Labelled ingredients for millionaire's shortbread including chocolate, oil, golden syrup, salt, white sugar, condensed milk, light brown sugar, butter and flour.
  • Flour - Use all-purpose flour for the shortbread base.
  • Butter - Use salted or unsalted butter according to your taste. 
  • White Sugar - Regular granulated sugar for the shortbread. (Caster sugar in the UK). 
  • Light Brown Sugar - This recipe uses brown sugar in the caramel filling to give a deeper flavor and a softer texture. 
  • Golden Syrup - This is traditional in caramel shortbread as it's a common ingredient in the UK. If you don't have it, you can substitute with corn syrup - light or dark. 
  • Condensed Milk - Sweetened condensed milk gives a velvety mouthfeel that you don't always get with a straight caramel. It's also more forgiving during the cooking process and less likely to burn or crystallise. 
  • Oil - Use a flavorless oil like vegetable oil or canola oil.  A dash of oil added to the chocolate layer helps it to set up into a slightly soft chocolate so you can bite into it without squishing the gooey caramel out.
  • Chocolate - I like to use dark chocolate because it balances out the sweetness of the caramel. But you can use bittersweet chocolate or even milk chocolate if you prefer. Make sure you use real chocolate, not chocolate chips or candy bars, as these contain extra ingredients that will stop them from melting properly. 

Make sure your butter is room temperature before beginning. 

See the recipe card for the measurements and instructions. 

Three pieces of millionaire's shortbread from the side, one is on top of the other two, showing the clean layers inside.

How to Make Millionaire's Shortbread

I have broken down this millionaire's shortbread recipe into sections with step-by-step pictures for each part so you can master every layer.

Make the Shortbread Layer

The shortbread layer uses my traditional Scottish shortbread recipe for a buttery shortbread base that is perfectly crumbly. It uses a softened butter method, so you don't need to use a food processor or pastry cutter to work with the cold butter. 

Sugar and butter creamed together to make scottish shortbread.

Mix Butter and Sugar

Beat the room temperature butter in a large bowl just to soften it a little more. Then add the sugar and mix it in. 
Don't try to cream it, just mix enough to combine. 

A ball of shortbread dough in a large bowl.

Add Flour

Sift in the flour and mix it in just until it comes together into a raggedy dough. Be very careful not to overmix. 

Tip the shortbread dough into the prepared pan lined with parchment paper.

Shortbread dough pressed into a square pan with fork pricks all over it.

Press Down

Press the dough down firmly to make an even layer of shortbread, then prick it all over with a fork. 

Docking the shortbread like this helps steam to release so it can bake evenly without getting soggy. 

Baked shortbread in a square pan to be the base for millionaire's shortbread.

Bake Shortbread

Bake the shortbread for 30 minutes or until the very edges just start to turn golden brown. 

Shortbread is supposed to be quite pale, so you don't want it to be golden or over, or it will be overbaked. 

Let the shortbread cool in the pan completely. 

How to Make the Caramel

The caramel layer is the most crucial element of a perfect millionaire's shortbread. It's a little different than a traditional caramel recipe, but just follow these step-by-step instructions and tips to know how to get it just right.

Cooking caramel in a saucepan to make millionaire's shortbread.

Melt Butter and Sugar

Add the brown sugar, butter, and golden syrup to a medium saucepan over medium heat. 

Bring to a boil, stirring occasionally, until the butter has melted and the sugar has completely dissolved. 

You'll know it has dissolved when you run your spoon across the bottom of the pan and it no longer feels grainy. 

Adding condensed milk to caramel to make the filling for millionaire's shortbread.

Add Condensed Milk

Remove the melted butter and sugar mixture from the heat and slowly add the condensed milk and salt.

Stir to combine, then return to the heat. 

Caramel filling coating the back of a spoon to show it is ready.

Boil the Caramel

Bring back to a boil, stirring constantly to avoid burning the caramel on the bottom of the pan. 

Let it boil until it thickens and the bubbles start to look like large, bursting craters on the surface. This should take about 5-7 minutes. 

When your caramel is ready, it will be a little darker in color and should coat the back of your spoon in a satin-like layer. 

See more tips below on how to know your caramel is ready. 

Tip:

Don't worry if you see little brown specs in your caramel. It's not burnt! Those are toasted milk solids, which will add a beautifully nutty brown butter flavor to your caramel. 

Pouring hot caramel over shortbread base to make millionaire's shortbread.

Pour Caramel

Remove your caramel from the heat and let it sit in the pan for 1-2 minutes to cool slightly. 

Then pour on top of the shortbread base and smooth it out to the edges to make a nice, even layer. 

Let it cool to room temperature, then place it in the refrigerator to chill for 1-2 hours. 

Add the Chocolate Topping

The topping of caramel shortbread should be real chocolate (not chocolate ganache!) We'll mix it with a little oil to help it set soft enough to give way just enough for a satisfying bite without squishing out the caramel.

Melting chocolate in a glass bowl.

Melt Chocolate

Put the chopped chocolate in a heatproof bowl and melt it in short bursts in the microwave (30 seconds), stirring in between until completely melted. 

Then stir in the vegetable oil. 

Pouring melted chocolate over the caramel layer to make millionaire's shortbread.

Pour Chocolate

Pour the melted chocolate over the top of the chilled caramel and use an offset spatula to smooth it out to cover the whole surface. 

If you want to, you can drizzle some white chocolate on top for a pretty pattern, or sprinkle some flaky sea salt on top. 

Finished millionaire's shortbread with melted chocolate poured on top.

Chill

Put the whole thing back in the fridge for another hour so everything can completely set. 

How To Know When the Caramel Is Ready

The trick to making the perfect millionaire's shortbread is knowing when your caramel is just right. 

If you undercook it, the caramel will be too soft and will ooze out when you bite it.  If you overcook it the caramel will be hard and brittle, and too difficult to bite into. 

There are a lot of signs you can look for to know your caramel is that Goldilocks level of just right. These tips are for this specific kind of caramel - but if you are interested in knowing more about the process in general, you can check out my homemade caramel sauce recipe.

  • Color - A lot of recipes will use the color of the caramel as the main indicator for when it is ready. Because this recipe uses light brown sugar instead of white sugar, it's a bit harder to tell this way. The caramel will darken slightly in color, but it's best to look for the textural cues that it's ready. 
  • Bubbles - In the beginning, the bubbles will look like a regular boil. As the caramel thickens, they will become slower and larger and look like they are bursting on the surface. Once you see these thicker bubbles, you likely only need another minute or two of boiling. 
  • Lines - If you can draw a line across the bottom of the pan with your spoon, the caramel is ready. It will fill in again pretty much immediately, but once you can do this, it's a good sign the caramel is thick enough. 
  • Coating - The caramel should coat the back of your spoon in a nice, satiny layer. If it all just dribbles off immediately, it's not there yet. 
  • Temperature - If you want to, you can use a candy thermometer to test the temperature of your caramel. It needs to be at the soft ball stage, which is 235°F - 240°F / 112°C - 115°C. 
  • Spoon Test - A foolproof way to test if your caramel is ready is to dip a cold spoon into the caramel mixture and let it sit for 30 seconds or so. Once it cools down, it should be soft and pliable. If it is still runny, then it needs longer. If it goes hard, then it is overdone. 
A piece of millionaire's shortbread with a bite taken out of it, showing the perfect texture of the caramel filling.

How To Slice Millionaire's Shortbread

The recipe might be simple, but slicing Millionaire's Shortbread cleanly? That's where things can fall apart - literally. After making thousands of these in the bakery, I've learned that a few pro tips make all the difference between flawless layers and a gooey mess on your countertop.

Here's how to get those perfect, bakery-style slices:

  1. Chill thoroughly first - Ideally, let the shortbread chill overnight so the layers are fully set. Take it out of the fridge about 20 minutes before slicing to soften just slightly.
  2. Score the chocolate layer - Use a small, sharp knife to gently score a line through the chocolate. Go over the same line a few times until you reach the caramel - this helps prevent the chocolate from cracking and the caramel from squishing out.
  3. Use a hot knife - Run a large, sharp knife under hot water, then dry it off. Press straight down through the caramel and shortbread in one smooth motion, applying even pressure.
  4. Wipe and reheat between cuts - Clean the knife and reheat it between each slice for the neatest results.

With just a little patience and the right technique, you'll get picture-perfect caramel squares every time!

A piece of millionaire's shortbread from the side, showing the distinct layers of shortbread, caramel and chocolate.

Millionaire Shortbread Science

There are a lot of small steps in this millionaire's shortbread recipe that have been chosen carefully and with very good reason. Here is some of the science behind those steps that will lead you to caramel slice perfection. 

  • Using the softened butter method is not only easier, but it also helps the butter coat the flour particles, which limits gluten formation and gives a melt-in-your-mouth texture. I use this for every shortbread recipe.
  • This recipe uses light brown sugar instead of white sugar. This not only gives it a richer flavor, but brown sugar contains more moisture, which helps keep the caramel soft. 
  • Melting the butter and sugar before adding the condensed milk allows the sugar to dissolve fully and start caramelizing to make a smoother, richer caramel that is less likely to split. It also lets the butter start to brown slightly to add amazing flavor to the caramel. 
  • Adding oil to the chocolate helps it to set just soft enough that you can slice it and bite into it without the chocolate breaking or the caramel being squished out of the sides.

Troubleshooting

Soggy Shortbread Base - This could be a few things. If the shortbread is underbaked or it wasn't docked with a fork before baking, it could end up soggy right off the bat. If it seems ot go soggy later, it could be that the caramel was poured over top before the shortbread had cooled, which can cause the caramel to seep into the shortbread and make messy, undefined layers. 

Caramel Seizing - If your caramel seizes up when you add the condensed milk, it's likely due to the difference in temperature. That is why it is important to remove the caramel from the heat and pour the condensed milk in gradually to prevent a temperature shock. 

Caramel Too Soft - If your caramel doesn't set up nicely and is too runny, it was not cooked for long enough. See my section on exactly how to know when the caramel is ready. 

Caramel Too Hard - If the caramel is tough or chewy, it was likely cooked for too long. See my section above on how to know when it is ready. 

Messy Caramel - The caramel needs to sit for 1-2 minutes after coming off of the heat to cool down just a little. If you pour it onto the shortbread base right away it could soak into the caramel or run down the edges of the pan, creating a mess. Don't let it sit for more than 2 minutes, though, or you'll have a sticky caramell that might not spread well.

Equipment

How to Store Millionaire Shortbread

Store your millionaire bars in an airtight container at room temperature. They should be good like this for up to a week. 

FAQs for Millionaire's Shortbread

Why is it called Millionaire's Shortbread?

Millionaire's Shortbread bars get their name because they are so insanely rich! Which makes sense, these indulgent caramel squares are so decadent that a few bites is more than enough to satisfy a serious sugar craving.

What are the layers of Millionaire's Shortbread?

Millionaire's shortbread consists of three layers of buttery shortbread, golden caramel, and dark chocolate topping.

What are other names for Millionaire's Shortbread?

Millionaire's shortbread has many names! It is also often called caramel squares, caramel shortbread, or caramel slice.

More Caramel Desserts

Looking for more ways to satisfy your caramel craving? Try some of these:

Recipe

Three pieces of millionaire's shortbread in a stack, the middle one has a bite taken out of it to show the gooey caramel filling.

Millionaire's Shortbread

Recipe Author: Jules Grasekamp
4.6 from 11 votes
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Prep 10 minutes
Bake 50 minutes
Total 1 hour
Authentic Scottish Millionaire's shortbread recipe with buttery shortbread, perfectly gooey caramel and rich dark chocolate topping.
Makes 16 squares

Ingredients

For the Shortbread
  • 2 cups All Purpose Flour 250g
  • 2 sticks Unsalted Butter 227g (room temperature)
  • ½ cup Granulated Sugar 100g
For the Caramel
  • 1 cup Light Brown Sugar 220g
  • 2 sticks Unsalted Butter 227g
  • ⅓ cup Golden Syrup 110g (or corn syrup)
  • 1 can Condensed Milk 14oz / 395g
  • ½ teaspoon Salt
For the Topping
  • 10 oz Dark Chocolate 280g (chopped)
  • 1 tablespoon Vegetable Oil
  • 1 teaspoon Sea Salt optional

Equipment

Instructions

Make the Shortbread
  1. Preheat oven to 340°F / 170°C (150° fan-assisted) and line an 8-inch square pan with parchment paper.
  2. Put the room temperature butter in a mixing bowl and beat it lightly with a wooden spoon to soften it.
    You can do this in a stand mixer if you prefer but you have to be very careful not to overmix.
    2 sticks (227 g) Unsalted Butter
  3. Add the sugar and mix it into the softened butter. Don't beat too much, we aren't trying to cream it, just to combine.
    ½ cup (100 g) Granulated Sugar
  4. Add the flour and mix it gently just until it incorporates. The easiest method is actually to use your hands to bring all the ingredients together until they start to form a scraggly dough.
    2 cups (250 g) All Purpose Flour
  5. Use your hands to bring it together into one cohesive ball of dough. Be careful not to overwork it.
  6. Tip the scraggly dough into your prepared baking pan and press it down into all the edges until it forms a nice, even layer of dough on the bottom of the pan.
  7. Dock the shortbread dough by using a fork to prick holes all over it - this will help steam to release and the shortbread to bake more evenly.
  8. Bake for 30 minutes or until just starting to turn golden brown at the very edges.
    Let the shortbread cool completely.
Make the Caramel
  1. Put the butter, light brown sugar, and golden syrup in a pan over medium heat, stirring occasionally until the butter has melted and the brown sugar has completely dissolved.
    You'll know the sugar has dissolved because the mixture will no longer feel grainy when you run your wooden spoon across the bottom of the pan.
    1 cup (220 g) Light Brown Sugar, 2 sticks (227 g) Unsalted Butter, ⅓ cup (110 g) Golden Syrup
  2. Once the sugar has dissolved, remove from the heat and stir in the condensed milk and salt slowly.
    1 can Condensed Milk, ½ teaspoon (½ tsp) Salt
  3. Return the pan to the heat and bring to a boil, stirring constantly to avoid burning the caramel on the bottom of the pan.
  4. Let the caramel boil until it thickens and the bubbles start to look like large, bursting craters on the surface. This should take about 5-7 minutes of boiling.
    When your caramel is ready, it should be a little darker in color and should coat the back of your spoon in a satin-like layer.
    See the post above for more tips on how to know if your caramel is ready.
  5. Remove the caramel from the heat and let it sit for 2-3 minutes to cool slightly. This will make it a more workable consistency that won't run down the sides of the pan.
  6. Pour the caramel over the cooled shortbread base and smooth it out to the edges.
  7. Let the caramel come to room temperature, then transfer to the fridge to chill for 1-2 hours, or until completely set.
Add Chocolate Topping
  1. Once the caramel has set, melt the dark chocolate in 30-second bursts in the microwave, stirring in between until completely melted. Then stir in the vegetable oil.
    10 oz (280 g) Dark Chocolate, 1 tablespoon Vegetable Oil
  2. Pour the melted chocolate over the cold caramel shortbread.
    Optional: For an extra touch, you can sprinkle with a little flaky sea salt, or drizzle some white chocolate on top of the dark chocolate to make a pretty pattern before it sets.
    1 teaspoon Sea Salt
  3. Return the millionaire's shortbread to the fridge to chill for another hour before slicing.

Nutrition

Calories551kcalCarbohydrates59gProtein5gFat34gSaturated Fat20gPolyunsaturated Fat2gMonounsaturated Fat9gTrans Fat1gCholesterol70mgSodium260mgPotassium260mgFiber2gSugar43gVitamin A779IUVitamin C1mgCalcium104mgIron3mg

Notes

Important Notes:
  • Let the shortbread cool completely before pouring the caramel over it. 
  • Let the caramel sit for 1-2 minutes before pouring over the shortbread.
  • Pay close attention to the signs that the caramel is cooked enough, if it is overcooked it will be too hard, and if it is undercooked it will run right out of the middle when you take a bite. See my section above on how to know exactly when it's done. 

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Comments

    4.64 from 11 votes (10 ratings without comment)

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  1. Molly

    I was just in Scotland and loved the Millionaire Shortbread! Quick question- in the USA, we have sweetened condensed milk (concentrated milk sweetened with sugar) and we have evaporated milk (which is just condensed milk without added sugar). Is this recipe calling for evaporated milk?

    Reply

    • Jules Grasekamp

      Hi Molly,

      Amazing! I hope you loved your trip to Scotland!
      We have the same here - it's the sweetened condensed milk you want 🙂
      Hope you love the recipe when you try it!

      Jules

      Reply

  2. Freya

    1 star
    Using the gram conversions did absolutely not work, shortbread was awful nothing like shortbread. Not sure if it’s incorrect conversions but did not work. Had to throw away

    Reply

    • Jules Grasekamp

      Hi Freya,

      The gram measurements aren't conversions - as a professional recipe developer, all of my recipes are made and tested with grams. We add cup measures onto the site as a lot of people in the US are put off by using a kitchen scale, but I do always recommend to measure by weight for accuracy.

      Can i ask what went wrong with the shortbread? Being Scottish, I have a lot of shortbread recipes on the site and am very proud of this shortbread recipe which has been tested A LOT. I'd be happy to help you troubleshoot to figure out what went wrong?

      Jules

      Reply

  3. Lynda

    Can I use a thick store bought caramel sauce rather than making my own. Mrs. Richardson makes a rather thick salted caramel sauce.

    Reply

  4. Pam

    Question
    In the recipe for pistachio cupcakes, is pistachio butter interchangeable for pistachio paste? I can't wait to try these; we have 100% chance of precipi tation today; perfect opportunity

    Reply

    • Jules

      Hi Pam, I'm so excited for you to try them! Rainy days are always great for baking something deliiocus!
      Yes pistachio paste or pistachio buttter, they are the same thing! Just make sure it isn't 'pistachio cream' or something with lots of added ingredients. Normally the ingredients will be just pistachios. Happy baking! And let me know how they turn out 🙂

      Reply

  5. Rose

    Don't know what the measurements for the sugar r and the corn syrup ?? Rose

    Reply

    • jules

      Hi Rose, that's strange, they are both in the recipe card.
      Sugar in the shortbread is 1/2 cup (100g), golden sugar in the caramel is 1 cup (220g) and the corn syrup is 1/3 of a cup (117g). Hope this helps! Let me know if it's not displaying properly for you on the recipe card. 🙂

      Reply

    • Sarah

      Thanks for asking this. I thought those were right but am glad for the conversion.

      Reply

      • Jules

        Hi Sarah, there's a little toggle at the top of all my recipes where you can switch between cups and grams 🙂 Hope this helps and happy baking!