Wash plums, dab dry, quarter and stone them. Cut plum quarters into thin slices. Mix marzipan and double cream. Mix quark, sugar, vanillin sugar, milk, oil and salt.
Mix flour and baking powder, add and knead everything into a smooth dough. Roll out to a rectangle (approx. 36x48 cm) on a floured work surface and cut into 8 rectangles (approx. 12x18 cm).
Spread each half of a rectangle with some marzipan and cover with plums. Separate the eggs. Brush the edges of the dough with egg white, fold over and press down with a spoon handle. Cut the top side of the dough several times with a knife and place it on a baking tray lined with baking paper.
Bake in the preheated oven (electric: 200 °C / gas: level 3) for 15-20 minutes. Mix egg yolk and cream and brush the particles with it after about 10 minutes. Let them cool down on a cake rack and serve dusted with icing sugar.
Results in 8 pieces.