In a food processor, blend lady fingers until you have fine crumbs. Set aside 2 tablespoons to sprinkle on the truffles later. Transfer the remaining crumbs to a bowl. Add the sugar and whisk until combined.
Using a hand mixer (or stand mixer) add the mascarpone cheese to the bowl and mix until fully incorporated. Add the espresso one tablespoon at a time. You do not want a goopy consistency. It should be similar to a soft cookie dough. Transfer the mixture to a tupperware container and place in the fridge for 45 minutes to an hour.
Line a baking sheet with wax paper or parchment paper. Remove the mixture from the fridge (it should be firmer now). Start to shape the mixture into 36 (1-inch) balls and place them on the prepared baking sheet. Freeze for 10 minutes.
Melt the chocolate (see tips here) and stir in the espresso powder. Dip a cold tiramisu truffle into the melted chocolate and transfer it back to the baking sheet. (I use these dipping tools) Sprinkle the truffle with the crushed lady fingers you set aside earlier. Repeat for the remaining truffles.
Place the baking sheet in the fridge for a 5 to 10 minutes for the chocolate to harden. Store tiramisu truffles in an airtight container in the fridge.
¹ I recommend Stella D'Oro Margherite lady fingers. I found them at my local grocery store. ² Cream cheese (3/4 cup or 6 ounces) can be substituted for mascarpone. ³ Strong coffee or coffee liquor can be used in place of espresso.Balls of dough can be frozen in a closed container (or covered cookie sheet) for up to two weeks. Truffles last about a week and should be refrigerated. You can bring them to room temperature before serving if preferred.