German Marble Cake

Ingredients: 200 g soft unsalted butter160 g sugar1 sachet vanilla sugar1 pinch of grated lemon peel2 tablespoons of milk6 eggs (each separated into egg white and egg yolk)1 pinch of salt120 g sugar280 g flour1/2 sachet baking powder100 ml lukewarm milk20 g cocoa powder Preparation: Cream the really soft butter …