*The filling is made by folding whipped cream into chilled vanilla pastry cream. This means the pastry cream must be made ahead of time so it has the chance to cool. Make the pastry cream at least 2 hours in advance. If this is your first time making pastry cream, you might like to check out my vanilla pastry cream recipe post for extra tips and guidance.
Whisk the egg yolks together with the cornstarch and sugar until pale and thick. It might look at first like it won't go smooth, but just keep whisking.
Heat the milk in a saucepan over medium heat until scalding hot - this means there is steam rising from it and tiny bubbles appearing on the surface. Don't let it boil.
Gradually pour the hot milk into the egg yolk mixture, a little at a time, whisking as you go. It's important not to add it too quickly to avoid scrambling the eggs.
Once all the milk has been added, pour the whole mixture back into the saucepan and continue to cook, whisking constantly until the pastry cream begins to thicken and boil with thick bubbles bursting on the surface.
Let the pastry cream boil for 1-2 minutes. It should be thick and glossy.
Remove from the heat and add the vanilla and salt. If you have any lumps in your pastry cream, you can pass it through a fine-mesh sieve to remove them.
Whisk in the butter.
Cover with plastic wrap, so the plastic is touching the surface of the pastry cream, and let cool. Then refrigerate for at least 2 hours or up to 72 hours.
Make the Donut Dough
Warm the milk to roughly body temperature and mix in the active dry yeast and 1 tablespoon of the sugar. Let it sit for 5-10 minutes or until it starts to froth up.If you are using instant yeast you can skip this step.
In the bowl of a stand mixer with a dough hook attachment, add the remaining sugar, salt, and eggs.
Once the yeast is frothy, pour the milk/yeast mixture into the mixer bowl and stir everything together to combine.
Add the flour and turn the mixer on low speed for 1 minute until it incorporates slightly.
With the mixer still on low speed, slowly drizzle in the melted butter.
Turn the mixer up to high speed and let it mix for 3-5 minutes or until the dough is no longer sticking to the side of the bowl.
Tip the dough out onto a lightly floured work surface and knead it by hand until it is no longer sticking to your hands.
Form the dough into a smooth ball and place it in an oiled bowl. Cover with plastic wrap and leave it on the countertop to rise until it has doubled in size ( 1-2 hours depending on the temperature of your kitchen.
Once the dough has doubled in size, check if it is ready by pressing on it lightly with your finger. If the indent disappears immediately, it needs longer to prove. If the indent comes back slowly and only about halfway, then it is ready to use.
Punch the dough to release the excess air then tip it onto a floured work surface and roll it out to ½ an inch thick.
Use a round cookie cutter (2½- 3 inches wise) to cut rounds out of the dough and place them on a lined baking sheet, with a little space between them. You can re-roll and cut out the scraps, but only once.
Cover the donuts loosely with plastic wrap or a kitchen towel and leave to prove again for roughly 45 minutes. Do the indent test again to see if they are ready and if not, leave them for another 15 minutes.
Fry the Donuts
Once the donuts are ready, uncover them and start heating up the oil. Make sure the oil in your pan is at least 2-3 inches deep.
Using a candy thermometer, bring the oil to a temperature of 350°F / 180°C.
Next to your stovetop, set up a wire rack lined with paper towels (this is to absorb the excess oil).
Test out your first donut by lowering it gently into the oil with a metal slotted spoon. It should start to bubble around the edges.
Fry the donut until it is a pale golden brown color (it will continue to brown after). Then flip the donut over and fry the other side until it is the same color. This should take about 1-2 minutes per side.
I find the optimum temperature for frying these donuts is 325° - 340°F ( 165° - 171°C). Make sure you let the oil come back up to temperature in between donuts as it may cool down as you are frying.
Remove the donut from the oil and place on the wire rack lined with paper towels. Let cool for a minute or two then roll in sugar. Let them cool completely before filling.
Repeat with all the donuts, I don't recommend doing more than 2 or 3 at a time to help regulate the oil temperature.
Make The Filling
Remove the chilled pastry cream from the fridge and whisk it gently to bring it back to a smooth consistency.
Whip the cold heavy cream up to stiff peaks.
Fold half of the whipped cream into the pastry cream until almost completely combined, then fold in the other half of the whipped cream.
Use a long thin object like a chopstick or a metal straw to poke a hole in the side of each donut and move it around to create space in the middle.
Put the filling into a piping bag with any kind of nozzle and squeeze it into the donuts. Once the donut feels heavy you will know it is full.
Notes
Make sure you make the pastry cream in advance so it has time to chill before being combined with whipped cream to make the donut filling. Frying Temp - Some recipes say the optimal temperature for frying donuts is 375°F. I have tested frying these donuts at various temperatures and I consistently find that 325° - 340° is the best temp to fry them at. TroubleshootingI have a whole troubleshooting section in the blog post above for common mistakes and questions.