Add the baking powder to the flour in a bowl and mix the two together. Now add the soft butter cut into pieces, the sugar, the vanilla sugar and the eggs and knead everything into a crumble dough with your hands. Alternatively, the kneading hooks of the mixer can be used for this.
Spread two thirds of the crumble dough on a baking sheet lined with baking paper and briefly press it flat with your hands to form a sheet of dough. Let the baking sheet and the rest of the dough rest for a while and, if possible, keep it in a cool place.
In the meantime, wash and clean the strawberries and place in a large bowl. Halve larger strawberries. Wash and clean the rhubarb, cut into pieces about three centimeters in size and add to the strawberries.
Make a mixture from 4 tablespoons of sugar and 2 tablespoons of pudding powder, pour this over the fruit and mix everything carefully - without crushing the strawberries. Place the fruit on the dough base and distribute evenly. Then put the remaining crumble on top.
Bake the cake at 180 degrees, fan-assisted 160 degrees, for 40 - 45 minutes.
Let the finished cake cool and then serve with whipped cream.
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