Wash the plums, drain, cut in half and remove stones. Cut marzipan into large pieces. Knead marzipan, flour, butter, 40 g icing sugar, vanillin sugar, bitter almond flavour and egg with the dough hooks of the hand mixer. Briefly knead the dough with your hands and roll out into a circle (32 cm Ø) on a floured work surface. Line a tart mould (28 cm Ø) with a removable base, pressing the edge down. Prick the dough several times with a fork, sprinkle with breadcrumbs. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 10 minutes, remove from oven.
Spread the plums on the cake base. Sprinkle with flaked almonds and 2 tablespoons of sugar. Bake in the oven at the same temperature for about 20 minutes. In the meantime beat the egg whites until stiff and pour in 100 g sugar. Pour in splodges onto the tart. Bake in the oven at the same temperature for about 10 minutes. Let it cool down and sprinkle with 10 g icing sugar