Add the sugar to the egg yolks. Beat well until the mixture is light and creamy.
Add the mascarpone and half of the cognac or brandy, and beat well.
With clean utensils, beat the egg whites until stiff. Fold the beaten egg whites into the mascarpone mixture.
Pour espresso into a shallow dish along with the remaining cognac and 1 teaspoon of the cocoa powder. Stir well.
Quickly dip each lady finger in the espresso mixture, working one at a time, and line the bottom of a glass dish,
approximately 20cm round or square.
Once the bottom of the dish is covered in an even layer of espresso-soaked lady fingers, top with 1/2 of the mascarpone mixture.
Dust with 1/2 of the cocoa. Repeat with another lady finger layer, then finally the remaining mascarpone
and a final dusting of cocoa powder.
Chill in the fridge for about 4 hours, then serve!
