Knead nuts, flour, baking powder, 65 g sugar, egg and butter in flakes to a smooth dough. Roll out the dough to a circle (26 cm Ø) on a floured work surface. Place on a greased springform pan (26 cm Ø) and prick several times with a fork. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 15-20 minutes. Remove from the oven, place on a cake rack and allow to cool. In the meantime, sort out the raspberries.
Soak gelatine in cold water. Mix yoghurt, quark and 180 g sugar. Squeeze out the gelatine and melt at low heat. Remove from the stove. Stir 1/3 of the yoghurt mass drop by drop into the gelatine. Run into the remaining yoghurt mass and stir in. Chill for about 5 minutes until the mass begins to gel. Whip cream until stiff and fold into the gelatine mass in portions. Remove the cake base from the springform pan, place on a cake plate and enclose firmly with a cake ring. Spread 450 g raspberries evenly on top, sprinkle with 1 tbsp sugar. Add the yoghurt cream mixture, spread loosely and chill for about 4 hours.
Run into the remaining yoghurt mass and stir in. Chill for about 5 minutes until the mass begins to gel. Whip cream until stiff and fold into the gelatine mass in portions. Remove the cake base from the springform pan, place on a cake plate and enclose firmly with a cake ring. Spread 450 g raspberries evenly on top, sprinkle with 1 tbsp sugar. Add the yoghurt cream mixture, spread loosely and chill for about 4 hours. Remove the cake from the cake ring. Decorate with remaining raspberries and lemon balm and dust with icing sugar
Waiting time approx. 5 hours