Wash, halve and stone the plums. Cut the plums into quarters again. Mix quark, milk, oil, 50 g sugar, vanillin sugar and salt. Mix flour and baking powder and stir about half into the quark mixture.
Knead in the remaining flour. Roll out the dough on a floured work surface until round (approx. 30 cm Ø). Line a greased springform pan (26 cm Ø) with the dough, press firmly at the edges. Mix egg yolk and 100 g sugar.
Sprinkle the almonds on the ground and spread the plums on top. Sprinkle the egg yolk-sugar mixture over the plums. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 30 minutes, covering the edge after half the baking time if necessary.
Remove the cake, remove from the edge and let it cool on a cake rack. Dust with icing sugar before serving. Whipped cream tastes good with it.