Whisk the yolks and sugar until the mixture whitens.

Add the mascarpone and mix.

Beat the egg whites until very stiff and gently add to the mixture.

Dip the biscuits in the coffee and line the bottom of a dish or individual glasses.

Cover with a layer of mascarpone/egg mixture,

place another layer of biscuits and cover with a second layer of mascarpone. And start the operation again one last time.

Place in the refrigerator for at least 8 hours.

Before serving, sprinkle with cocoa.