Warm 100 ml milk lukewarm. Put 500 g flour in a bowl, make a well in the middle. Crumble in the yeast, mix with a little flour from the edge, 25 g sugar and lukewarm milk. Cover and let rest in a warm place for about 15 minutes.
Melt 100 g butter. Pour in 150 ml of milk. The milk and butter mixture should be lukewarm. Put 50 g sugar, egg, salt and milk-butter mixture on the edge of the flour and knead into a smooth dough. Cover and let rise in a warm place for about 30 minutes.
Melt 150 g butter for the crumble dough. Mix 300 g flour, 125 g sugar and vanilla sugar in a bowl. Pour in the butter and knead to make crumbles.
Wash, halve and stone the plums. Grease the oven`s drip pan (approx. 32 x 38 cm) well. Roll out the dough on a floured surface to the size of the drip pan.
Place the sheet of dough in the drip pan. Spread the plums on top like a roof tile, sprinkle with 25 g of sugar and the sprinkles. Cover and let rise for another 10 minutes.
Bake in the preheated oven (electric stove: 200 °, convection: 175 °, gas mark 3) for 30-35 minutes. Let cool down. Cinnamon cream tastes good with it.