Clean and wash the rhubarb, drain well and cut into pieces. Mix with 40 g sugar and set aside. Drain the peaches in a sieve and cut in half. Cream fat and 150 g sugar with the whisk of the hand mixer.
Add lemon zest. Stir in the eggs one by one. Mix flour, starch and baking powder and stir into the mixture. Put the dough on a greased baking tray (28x33 cm) and smooth it down. Spread rhubarb and peaches on top.
Mix the egg yolks, sour cream, remaining sugar and vanillin sugar. Pour evenly over the fruit topping. Bake in the preheated oven (electric oven: 200 °C/ gas: level 3) for approx. 30 minutes. In the meantime, beat egg whites until stiff, add sugar and finally stir in lemon juice.
Spread the meringue with a teaspoon as tuffs on the cake. Bake for another 5-7 minutes at the same temperature until the meringue tuffs are lightly browned. Makes about 12 pieces.