Whisk together the egg yolks, mascarpone, yoghurt, white wine and 100ml of the marsala wine in a large jug
In a shallow bowl or dish, stir together the coffee and remaining marsala. Dip the biscuits into this mixture briefly and then srrange them in a single layer in a large dish, 21x28cm or 23cm square or small glasses.
pour over some of the cream mixture until the biscuits are just covered. Top with another layer of coffee-soaked biscuits and then more cream.
Repeat these layers until all the cream has been used up, finishing with a layer of cream
Dust generously with the cocoa powder and chill for at least 24hours before serving.