How to make the cake mix:
Mix the butter at room temperature with 200 g sugar and the vanilla sugar until creamy, gradually mix in the egg yolks. Mix two tablespoons of flour with the cake mix, add the milk and lemon peel and mix. Beat the egg whites until stiff, add the rest of the sugar and beat until you can cut the stiff peaks with a knife. Sieve the flour and baking powder together. Gently fold the stiff egg whites and flour into the cake mix. Divide the cake mix into two halves and stir cocoa powder, chocolate and the rum into one half. Fill a greased and floured cake tin with half of the light cake mix then add the dark cake mix followed by the rest of the light cake mix. Use a fork to make spiral shapes in the cake mix to create the marble effect. Bake for 50 to 60 minutes at 180° C. Once baked (check with wooden stick!) leave to cool down in the cake tin, then turn it upside down and sprinkle with icing sugar.
Best wishes of culinary success and enjoy the recipe!
The Oberhofer family
and the cooking team from Ritterhof with chef Leo