Preheat your oven to 180 °C / 356°F top to bottom heat.
Grease a Gugelhupf form, a cake ring or a loaf form with butter, and dust with a little flour or breadcrumbs, to prevent the dough from sticking later.
In a large bowl, using a stand or hand mixer, whisk the sugar, vanilla sugar (or extract) and butter until creamy.
Add the eggs one by one. Lastly add the sour cream.
Sieve the flour, salt, baking powder and baking soda into the mixture (Sieving the flour will make the cake more airy)
Pour or spead ⅔of the batter into your cake form.
With the remaining ⅓ add the cocoa powder and milk to the light dough and mix, until the batter is brown.
Pour the brown batter onto the light one. Using a fork, pull it through the cake in spiral motions to achieve the marble effect.
Bake the cake for about 45-60 minutes. The exact baking time varies between ovens. To test whether the cake is done, prick a skewer in the middle. If it comes out clean, it is done.
To decorate
Dust with some icing sugar or glaze with a chocolate glaze according to packet instructions.
Notes
Storage Instructions
Mamorkuchen keeps in an airtight container for 3-4 days. However, it is also a great cake to freeze. In the freezer, it should last for up to three months.