Make a batter from the first seven ingredients. Rub the marzipan into this dough with the help of a slicer and fold it into the dough. Pour into a springform pan lined with baking paper and smooth out. Spread the halved plums on the dough like a roof tile and sprinkle with flaked almonds.
Bake in the preheated oven for approx. 60-70 minutes. Make a stick test and cover with aluminum foil if the dough is too dark. As soon as the cake is baked, take it out of the oven and sprinkle with sugar.