Mix the sugar, vanilla sugar and eggs with the hand mixer until frothy, then add the softened butter. Add eggnog, flour, baking powder, the grated block chocolate and the ground nuts and mix everything together.
Fill the dough in a greased and crumbled Gugelhupf springform pan and bake at approx. 180 ° C (fan oven) for approx. 45 - 50 minutes. After the cake has cooled down, spread the couverture and let it cool down.