Brush a cake form with a diameter of about 11″ (30 cm) with melted margarine, sprinkle it with flour and heat the oven. Combine the margarine with a cup and half of sugar, the egg yolks, liqueur, whiskey or brandy and vanilla sugar.
Stir until the sugar dissolves and add the milk and cocoa. Beat the egg whites and add them to the above mix. Add the flour and baking soda and stir slowly. Transfer to the cake form and bake for 25-30 minutes at 356°F (180 °C).
Then remove and allow it to cool. Serve the cut pieces on a plate and pour on the prepared in advance cocoa sauce made from 1 tablespoon of cocoa, diluted with a little liqueur or brandy and a little sugar.