Preheat oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer). Place 1 paper baking tin in each of the recesses of a muffin baking tray (12 recesses).
Cut off 20 g of chocolate with a peeler and set aside. Coarsely chop the remaining chocolate, melt it with butter in a small pot while stirring at low heat. Pour into a mixing bowl, let cool down briefly.
Stir 250 g sugar, 1 packet of vanilla sugar, 1 pinch of salt and eggs into the chocolate butter. Mix flour and baking powder, stir in briefly.
Spread the dough into the tins and bake in a hot oven for about 20 minutes. Remove the muffins, prick them often with a wooden skewer and sprinkle them with kirsch while still hot. Lift them out of the cups and let them cool down.
Wash and drain the cherries. Mix cream stiffener and 1 sachet of vanilla sugar. Whip the cream until stiff, allowing the cream stiffener mixture to trickle in. Stir mascarpone and 50 g sugar until smooth. Fold in the cream.
Pour the cream into a piping bag with perforated spout. Spray 1 tuff on each muffin, place cherries on top and sprinkle with chocolate shavings.