Separate eggs, beat egg whites and 3 tablespoons of water until stiff, add 100 g sugar and vanillin sugar. Gradually fold in the egg yolks. Mix flour, cornstarch and baking powder, sieve onto the egg foam and fold in. Line the bottom of a springform pan (26 cm Ø) with baking paper. Pour in the sponge mixture and smooth it down. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: not suitable/ gas: level 2) for 20-25 minutes.
Let them cool down. Cut the sponge cake horizontally once and place a springform pan rim or cake ring around the bottom. Wash, clean and pat dry the blackberries. Put yoghurt into a mixing bowl, sprinkle in sauce powder while stirring and stir vigorously for about 1 minute. Whip 500 g cream briefly, add 4 tablespoons of sugar and gelatine while stirring continuously and whip the cream until stiff. Fold in vanilla yoghurt. Fold in 2/3 of the blackberries under half of the cream. Set the remaining blackberries aside. Spread the cream on the bottom cake base and smooth it down. Place the second cake layer on top. Spread the second half of the cream and smooth it down.
Fold in vanilla yoghurt. Fold in 2/3 of the blackberries under half of the cream. Set the remaining blackberries aside. Spread the cream on the bottom cake base and smooth it down. Place the second cake layer on top. Spread the second half of the cream and smooth it down. Chill for at least 6 hours, preferably overnight. Remove the cake from the edge of the mould with a knife. Whip 150 g cream until stiff. Spread the cream on the edge of the cake with a notched spatula. Decorate the cake with set aside blackberries, pistachios and icing sugar
Chill for at least 6 hours, preferably overnight. Remove the cake from the edge of the mould with a knife. Whip 150 g cream until stiff. Spread the cream on the edge of the cake with a notched spatula. Decorate the cake with set aside blackberries, pistachios and icing sugar
waiting time approx. 7 hours