Beat the soft fat, sugar and vanilla sugar until frothy, beat in the eggs and salt. Mix flour with baking powder and stir in with milk. Pour the dough into a greased springform pan (26cm) and smooth it out. Halve, core, peel the apples and cut into wedges. Drizzle with lemon juice. Halve and stone the plums. Distribute in a ring on the dough. Prepare crumble from flour, sugar, cinnamon and fat and spread over the fruit. Bake in an oven preheated to 180 ° C with top-bottom heat for about 40 minutes. Please make a chopsticks test and cover if the cake gets too dark. (Streusel otherwise taste bitter)
Sprinkle with powdered sugar and enjoy lukewarm / cold with cream.