Drain the sour cherries in a colander. Let the chocolate slowly melt in a bowl in a water bath (do not boil or let it get too hot). Separate the eggs and beat the egg whites until stiff.
Mix the butter, sugar and egg yolks together until frothy. Gradually stir in the remaining ingredients without the cherries. Now stir in the liquid chocolate. Finally, carefully fold in the egg whites.
Spread the dough on a greased baking sheet. Now distribute the drained cherries on the dough and press in. Bake in the preheated oven at 175 ° C for about 45 minutes.