Wash and stone the plums. Mix 150 g flour, 100 g sugar, 1 sachet of vanilla sugar, add butter in flakes. First use the dough hooks of the hand mixer, then work into crumbles with your hands.
Mix quark, milk, oil, egg, 100 g sugar, 1 packet of vanillin sugar and salt. Mix 400 g flour and baking powder, slowly add half of it. Knead in the rest with the dough hook of the hand mixer.
Grease the fat pan of the oven (32 x 39 cm). Roll out the dough on a floured work surface to the size of the fat pan. Place in the baking tray. Spread the plums first, then the crumbles on top.
Sprinkle with sugar crystals, almond slivers and cinnamon. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 25-35 minutes. Whipped cream tastes good with it.