Knead 75 g sugar, 125 g flour, 75 g cold butter and brittle first with the dough hooks of the hand mixer, then with your hands to form crumbles. Chill for about 30 minutes
Cream 175 g soft butter, vanillin sugar and 175 g sugar with the whisks of the hand mixer. Stir in the eggs one by one. Mix 275 g flour and baking powder and stir in alternately with the buttermilk
Fill half of the dough into a greased and floured springform pan (26 cm Ø), smooth it down. Press hollows into the dough with a tablespoon. Put half of the plum puree into the hollows. Pour the rest of the dough evenly and carefully on top, smooth it down and press the hollows into the dough again. Pour the rest of the plum jam into the hollows. Marble the dough a little bit with a wooden skewer. Spread crumbles on top. Bake the cake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 40-50 minutes (stick test)
Take the cake out of the oven, remove from the springform pan and let it cool down on a cake rack. Dust with icing sugar before serving. Serve with whipped cream and cinnamon-sugar
Waiting time 2-3 hours