Wash, clean, halve and stone the plums. For the icing, mix pudding powder, 50 g sugar, sour cream and 3 eggs. For the crumbles, mix flour, 100 g sugar, vanillin sugar, baking powder and salt. Add 1 egg and butter in pieces. Knead everything first with the dough hooks of the hand mixer, then with your hands to crumbles. Take the yeast dough out of the packaging, unroll it with the baking paper directly onto a small, deep baking tray (approx. 19 x 34 cm; 2 litres capacity). Prick the dough several times with a fork.
Place the damsons close together. Spread the frosting over the plums and sprinkle with the crumbles. Bake in the preheated oven (electric range: 200 °C/ convection oven: 175 °C/ gas: level 3) for 40-45 minutes on the middle level. Cover the last 10 minutes of the cake if necessary. Leave to cool for about 2 hours. Cut into pieces, sprinkle with sugar crystals and serve decorated with mint. Whipped cream tastes good with it