Separate eggs. Beat the egg whites and 4 tablespoons of water with the whisks of the hand mixer until stiff. Add 100 g sugar and 1 packet of vanilla sugar. Add the egg yolks and stir in. Mix flour, starch and baking powder, sieve onto the egg mixture and fold in. Line the bottom of a springform pan (26 cm Ø) with baking paper. Fill in the dough and smooth it down.
Bake in the preheated oven (electric: 200 °C/ gas: level 3) for about 25 minutes. Let it cool down on a cake rack. In the meantime soak the gelatine in plenty of water. Mix the soured milk, lime juice and remaining sugar. Squeeze the gelatine and dissolve in a saucepan over a low heat. Stir into the soured milk mixture and chill for 30-45 minutes. In the meantime, wash and drain the currants and, except for a few blackcurrants for decoration, pluck them from the panicles with a fork. Sort the raspberries. Set aside about half of them for decorating. Whip 1 cup of cream and remaining vanilla sugar until stiff. When the soured milk mass begins to gel, carefully fold in the cream and fruit. Remove the sponge cake from the mould and cut it once crosswise. Heat the jelly in a pot and spread the bottom layer.
Sort the raspberries. Set aside about half of them for decorating. Whip 1 cup of cream and remaining vanilla sugar until stiff. When the soured milk mass begins to gel, carefully fold in the cream and fruit. Remove the sponge cake from the mould and cut it once crosswise. Heat the jelly in a pot and spread the bottom layer. Place a cake ring around the lower cake base and spread the berry soured milk mixture on top. Place the second cake base on top and press down gently. Leave to set in the fridge for about 2 hours. Remove the cake ring. Whip the remaining cream until stiff and spread it on the surface of the cake. Spread the rest of the raspberries and redcurrants on top and serve decorated as desired with half lime slices and lemon balm. Makes approx. 12 pieces
Place a cake ring around the lower cake base and spread the berry soured milk mixture on top. Place the second cake base on top and press down gently. Leave to set in the fridge for about 2 hours. Remove the cake ring. Whip the remaining cream until stiff and spread it on the surface of the cake. Spread the rest of the raspberries and redcurrants on top and serve decorated as desired with half lime slices and lemon balm. Makes approx. 12 pieces