Defrost the cherries. Cut off 20 g of chocolate with a peeler and set aside. Coarsely chop the remaining chocolate, melt it with butter in a small saucepan while stirring at low heat. Pour into a mixing bowl, let cool down briefly. Add 250 g sugar, 1 packet of vanilla sugar, 1 pinch of salt and eggs and stir into the chocolate butter with the whisk of the hand mixer. Mix flour and baking powder, stir in briefly.
Line the depressions of a muffin tray (12 depressions of approx. 100 ml each) with paper baking cups. Spread the dough into the baking cups and bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 20 minutes (stick test). Remove from the oven, allow to cool slightly and prick several times with a wooden skewer and sprinkle with the kirschwasser. Remove the muffins from the trays and let them cool on a cake rack.
Mix the cream firmer and 1 sachet of vanilla sugar. Whip the cream until stiff, while pouring in the cream firming mixture. Stir mascarpone and 50 g sugar until smooth. Fold in the cream. Mix the jam and half of the cherries and carefully fold into the mascarpone-cream mixture as streaks. Spread the mixture on the muffins with a tablespoon. Add the remaining cherries and sprinkle with the remaining chocolate.