For the plum cake, first wash, pit and quarter the plums. For the crumble, mix well soft butter, sugar, flour and cinnamon and put in a cool place. Now for the dough, beat sugar, vanilla sugar and eggs well.
Add yogurt and oil and continue beating. Now briefly stir in flour and baking powder. Spread the dough in a form (approx. 35×25) and cover densely with the plums.
Then spread the Srteusel on top and bake. Bake at 175 °C for about 35 minutes.