Mix together margarine and powdered sugar until foamy add 8 yolks and melted chocolate.
In bigger bowl, mix white of egg (it must be mixed well).
Combine chocolate mix and white of egg mix until it’s mixed well.
Take baking pan (covered with kitchen paper) and put 1st layer: soak Petit Beurre in coffee and put one by another until cover bottom. 2nd layer is chocolate mix then again soaked Petit Beurre, chocolate mix and finally Petit Beurre. It should be 3 layers of Petit Beurre and 2 of chocolate mix between them.
Put cake in freeze over night. When you take it from freezer, cover baking pan with serving tray and upside down. Remove kitchen paper and decorate with whipped cream.