Heat milk and fat for the yeast dough. Put flour, sugar, salt, vanilla sugar, egg and yeast in a mixing bowl, pour the lukewarm milk over it and knead with the dough hooks of the hand mixer.
Cover the yeast dough and let it rise in a warm place for about 30 minutes. In the meantime wash, stone and halve the plums. Melt the fat for the crumbles. Mix flour, sugar, almonds and salt and add the fat drop by drop.
Work into crumbles with the dough hooks. Knead the yeast dough again on a floured work surface and put the dough into a greased springform pan (26 cm Ø). Cover with the plums. Spread the crumbles on top and bake in a preheated oven (electric: 200 ° C / gas: level 3) for 30-40 minutes.
Let the cake cool down and remove from the mould. Makes about 12 pieces.