Separate eggs. Beat the egg white and mineral water until stiff and finally add 125 g sugar. Beat the egg yolks one after the other. Mix flour, cornstarch and baking powder, sieve onto the egg mixture and fold in carefully. Put the dough on a baking tray (32 x 36 cm) lined with baking paper and smooth it down. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 10-12 minutes.
Remove the sponge cake from the oven, turn out on a damp tea towel and let it cool down. In the meantime, heat up raspberries, except for a few for decoration, and 50 g sugar in a pot. Stir cherry nectar or water and groats powder until smooth. Bring raspberries to the boil, stir in the mixed powder and bring to the boil again. Simmer for 1 minute. Cut the sponge cake in half crosswise. Cover one half with a baking frame and add raspberry compote. Brush smooth. Place the second half of the sponge cake on top and press down a little. Put them in a cold place. Meanwhile, put the yoghurt and cream powder in a mixing bowl rinsed with hot water and whisk with the whisk of the hand mixer first for 1 minute at lowest setting, then for 3 minutes at highest setting.
Cut the sponge cake in half crosswise. Cover one half with a baking frame and add raspberry compote. Brush smooth. Place the second half of the sponge cake on top and press down a little. Put them in a cold place. Meanwhile, put the yoghurt and cream powder in a mixing bowl rinsed with hot water and whisk with the whisk of the hand mixer first for 1 minute at lowest setting, then for 3 minutes at highest setting. Carefully stir the chocolate shavings into the cream. Pour the cream onto the top sponge cake and smooth it down. Chill for 1 hour. Cut the cake into about 18 slices. Decorate with remaining raspberries and mint leaves dusted with icing sugar
Carefully stir the chocolate shavings into the cream. Pour the cream onto the top sponge cake and smooth it down. Chill for 1 hour. Cut the cake into about 18 slices. Decorate with remaining raspberries and mint leaves dusted with icing sugar
Waiting time approx. 1 hour