- First preheat the oven to 160 degrees and grease a bundt cake tin with a little butter.
- Mix the cocoa powder with 3 tablespoons of sugar and 3 tablespoons of milk in a small bowl or cup.
- Beat the eggs, separate them and stir the egg yolks in a separate bowl with the butter, the remaining sugar and the vanilla sugar until frothy. Mix the flour with the baking powder.
- Beat the egg whites until stiff and carefully stir into the egg yolk mixture alternately with the flour mixture and the rest of the milk.
- Now pour half of the dough into a separate bowl and mix with the prepared cocoa mixture.
- Now alternately fill both types of dough into the prepared Gugelhupf dish and pull a fork or chopstick through the dough a few times.
- Then the marble cake Bake in the preheated oven for approx. 60 minutes and at the end test with a wooden stick (needle test) whether this is done. Then turn the cake out of the pan and let it cool.
- Finally, cover the cake with the chocolate icing and decorate with colorful sprinkles.