Classic Italian dessert. This is a recipe I learned in a cooking class when I visited Rome.
Using a hand mixer or stand mixer with a whisk attachment, beat sugar and egg yolks for approximately 7 minutes, until the mixture is very smooth.
In a different bowl using the same mixer, whisk the egg whites until they're stiff enough that you can turn the bowl upside-down
Make some coffee according to your favorite coffee-making method, mix in a couple of spoonfuls of sugar according to your preference
Mix the mascarpone with the egg/sugar mixture until integrated
Fold in the egg whites just enough to incorporate them into the custard
Dip the lady fingers in the coffee, then place a layer of coffee-dipped biscuits in the bottom of a bowl or baking dish. Top the biscuits with a layer of the egg and mascarpone cream, then top with another layer of biscuits, and keep alternating layers until you've filled the bowl/dish