Heat the milk with 25g of the butter to lukewarm. Dissolve the yeast in the milk.In a bowl, combine 190g of the flour with salt and 20g of the sugar. Make a well into the middle and pour in the milk mixture. Mix with a little bit of the flour. Allow to rise for 15 minutes. Beat in one egg. Knead until the dough is smooth and pliable. Allow to rise for 45 minutes.

Mix 160g of flour with 80g butter and 40g sugar. Knead until well combined. Halve the dough and wrap each half into foil. Refrigerate for 15 minutes.

Dust a buttered tart form with flour. Knead 1 portion of the cooled dough into the yeast dough. Roll out and line the tart form with the dough. Allow to rise for 30 minutes.

Mix the sour cream with 2 eggs, 50g of sugar and the cornstarch. Sprinkle the cake bottom with the breadcrumbs. Spread with the cream and arrange the plums, slightly overlapping on top. Crumble the remaining dough and sprinkle the cake with the crumbles.

Bake in the preheated oven at 180°C for 35-40 minutes.