I made 2 more portions

1. First, preheat the oven to 180 degrees Celsius and generously grease your baking sheet.
2. Beat the butter and sugar in a large bowl until light and fluffy – this creates a wonderfully fluffy base.
3. Now add the eggs and carefully beat in the 4 egg yolks.
4. Mix the flour, vanilla sugar, and cocoa powder alternately into the butter, sugar, and egg mixture.
5. Now carefully fold in the stiffly beaten egg whites to keep the batter nice and light.
6. Spread the batter evenly on the baking sheet and place it in the oven for about 15 minutes, until your cake is golden brown.
7. After baking, let the cake cool and decorate it to your liking. Enjoy!