First mix the sugar and vanilla sugar with the eggs, then add the liquid fat and egg liqueur. Mix the dry ingredients in another bowl, then add the egg mixture and stir well.
Pour about half of the dough back into the other bowl and mix with any amount of cocoa, then adjust the consistency again with a dash of eggnog.
Bake in the oven preheated to 160 ° C (convection) for about 50 minutes (toothpick test!), Then let cool in the open oven.