Grease the fat pan (approx. 32 x 39 cm; at least 3.5 cm deep). Drain the cherries. Stir 250 g butter, 200 g sugar, vanillin sugar and 1 pinch of salt until creamy. Stir in the eggs one by one. Mix flour and baking powder and stir in alternately with 3 tbsp. milk briefly.
Spread half the dough on the fat pan. Stir the cocoa into the rest of the dough and spread it on the light-coloured dough. Spread the cherries on top. Bake in the preheated oven (electric cooker: 175°C/circulating air: 150°C/gas: level 2) for about 30 minutes.
Let it cool down.
Mix pudding powder, 50 g sugar and 5 tablespoons milk. Bring 450 ml milk to the boil. Stir in pudding powder and simmer for at least 1 minute while stirring. Pour into a bowl, place cling film directly on the surface.
Let it cool down.
Beat 250 g butter with a hand mixer for about 15 minutes until creamy. Stir the pudding briefly. Whip the butter by the spoonful with the hand mixer. Spread on the cake. Put in a cool place for about 4 hours.
Coarsely chop the chocolate coating and melt it with 30 g butter in a hot water bath. Allow to cool for about 15 minutes, then spread on the cake. Use a cake comb to draw wavy stripes into the chocolate coating.
Chill for at least 1 hour.