For the mulled wine, boil up wine, rum, white sugar, cinnamon, cloves, lemon juice, orange and lemon peel in a pot. Simmer for about 1 minute. Remove from heat, let it cool down and pour through a sieve.
For the dough, break chocolate into pieces. Melt with butter in a hot water bath. Let it cool down a little. Grease a ring cake tin (2 1⁄2 l capacity) and dust with flour. Mix flour, brown sugar, vanilla sugar, baking powder, 1 pinch of salt and cocoa.
Beat the eggs with the whisk of the mixer for about 3 minutes until frothy. Stir in cooled but still liquid chocolate butter bit by bit. Add flour mixture and 50 ml mulled wine and stir in briefly.
Put the dough into the mould and smooth it down. Bake in the preheated oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer) for 45-55 minutes (when testing with sticks, there should still be nice juicy crumbs on the wooden skewer).
Let the cake cool in the mould for 20-30 minutes, then carefully turn it out of the mould. Immediately sprinkle with the rest of the mulled wine and let it cool down.
For the decoration, cream cheese, soft butter and icing sugar with the whisk of the mixer until creamy. Gradually stir in the milk. Spread the icing on the ring cake. Chill for at least 1 hour.
Whip cream until stiff for serving. Pour into a piping bag with star-shaped spout. Decorate the cake with cream patches and fruit to taste.