Separate eggs. Beat the egg whites and 3 tablespoons of cold water until stiff, adding 120 g of sugar. Mix flour, baking powder and starch, sieve onto the mixture and fold in. Line a baking tray with baking paper and spread the mixture on it. Bake the cake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 8 minutes. Remove the cake from the oven, turn it over onto a sugared tea towel and remove the paper.
Let the sponge cake cool down. Sort the raspberries. Wash the lemon, grate dry and thinly grate the peel. Halve the lemon and squeeze it. Mix quark, 100 g sugar, lemon peel and juice. Halve the sponge cake crosswise. Place a cake frame around a base. Whip the cream until stiff. Stir in the gelatine with the whisk of the hand mixer. Fold 250 g raspberries and whipped cream into the quark. Spread the cream on the cake base, place the 2nd cake base on top and chill for about 1 hour.
Halve the sponge cake crosswise. Place a cake frame around a base. Whip the cream until stiff. Stir in the gelatine with the whisk of the hand mixer. Fold 250 g raspberries and whipped cream into the quark. Spread the cream on the cake base, place the 2nd cake base on top and chill for about 1 hour. Wash the lemon balm and dab dry. Dust the cake with icing sugar, cut into 15 pieces and decorate with about 40 raspberries and lemon balm