Melt the butter in the microwave, then pour into a bowl with both the sugars and mix together.
Add a splash of hot water to the espresso powder and mix together to form a paste. Add to the butter/sugar mixture and stir everything together.
Add the egg and vanilla. and stir until combined.
Add the dry ingredients and mix together until a soft dough forms.
Chill the dough for 30 minutes so it's easy to scoop.
Preheat oven to 350°F / 180°C and line a cookie sheet with parchment paper.
Spoon walnut-sized scoops of dough and roll them into balls in your hands. Place the cookie dough balls on the baking sheet, spaced well apart to allow for spreading.
Bake for 12 minutes, then remove from the oven and let sit on the tray for at least 10 minutes before moving to a wire rack to cool.
Make the Mascarpone Cream
Add the mascarpone, powdered sugar, amaretto, and vanilla to a bowl and mix together until it is smoothly combined with no lumps. Note: Some brands of mascarpone contain more liquid than others. If the mascarpone seems to contain a lot of liquid, make sure you drain off any excess liquid before using it.
In a separate bowl (or in a clean stand mixer), whip up the cream on medium speed just until stiff peaks start to form.
Fold the whipped cream into the mascarpone mixture until everything is combined.
Store in the fridge until ready to assemble and serve.
Assemble the Tiramisu Cookies
Make sure the coffee cookies are completely cool before adding the mascarpone topping.
Take the cold mascarpone cream out of the fridge and pipe or spread on top of the cookies. For a classic Tiramisu look, put the cream in a piping bag and snip off the end, about half an inch. Squeeze the mascarpone cream on top of the cookie in small little blobs.
Dust generously with cocoa powder through a sieve to complete the look.
Notes
You may want to bake the cookies in batches if you can't fit them all on one baking sheet. I like to use two baking sheets so I can have one cooling while the next one goes into the oven. When making the mascarpone cream, there is no need to bring your mascarpone to room temperature first, it should be fine cold. If you are unable to get rid of the lumps, let it sit out at room temp for 5 - 10 minutes before trying to mix again.