Beat yolks and sugar in stand mixer or electric beater for 10 minutes or until it changes from yellow to pale yellow (almost white), and is thick.

Add vanilla and mascarpone, beat until just combined and smooth. Transfer mixture to a bowl, set aside. This is your cream mixture.

In another bowl, add egg whites and beat until it's stiff (should be all white foam and with stiff peaks).

Add 1/2 the cream mixture into the egg whites. Gently fold through. When most incorporated, add the remaining cream mixture and fold through until just combined - don't bash out all the air in the egg whites!

Mix coffee and liquor together. Quickly dip biscuits in and line the bottom of a 8”/20cm square dish (I used rectangular glass baking dish)

Spread over half the cream, then top with another layer of coffee dipped biscuits.

Spread with remaining cream. Cover, refrigerate for at least 4 - 5 hours, preferably overnight.

Dust with cocoa powder just before serving - either before you cut or after placing onto serving plates.