Separate 4 eggs. Beat butter, 100 g sugar, salt and vanilla sugar with the whisk of the hand mixer until frothy. Stir in the egg yolks and 1 egg one after the other. Mix flour, baking powder and stir in. Cut the dough in half, spread one half in a greased springform pan (26 cm Ø) sprinkled with flour and smooth it down
Beat 2 egg whites until stiff, while pouring in 100 g sugar. Spread the egg whites on the dough and spread with a tablespoon. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 20 minutes. Let the base cool down a little, remove from the tin and let it cool down
Clean the mould and smooth down the remaining dough. Beat 2 egg whites until stiff, while letting 100 g sugar trickle in. Spread the egg whites on the dough and spread with a tablespoon. Bake at the same temperature for about 20 minutes. Let it cool down
Wash and clean the rhubarb and cut it into pieces about 2 cm long. Put juice, 50 g sugar, rhubarb in a pot and let it simmer at low heat for about 3 minutes. Stir starch with 4 tbsp. water until smooth. Remove the pot from the heat, stir in the starch and let it simmer for about 1 minute while stirring. Let it cool down a little bit
Wash, clean and halve the strawberries and fold them into the rhubarb compote. Let the mixture cool down. Place a cake ring around a base and spread the compote on top and chill for about 2 hours. Whip the cream until stiff, spread on the compote and carefully place the 2nd cake layer on top
waiting time approx. 2 3/4 hours