Separate the eggs for the sponge cake. Beat the egg whites, 100 g sugar, vanillin sugar and salt with the whisks of the hand mixer until stiff. Add the egg yolks and stir in. Mix flour, cornstarch and baking powder, sieve onto the egg foam and fold in carefully.
Place the dough on a baking tray lined with baking paper, smooth it down and bake in a preheated oven (electric range: 200 °C/ gas: level 3) for 10-12 minutes. Remove from the oven, turn out onto a damp tea towel sprinkled with residual sugar.
Carefully remove the baking paper. Turn over protruding corners of the tea towel. Let dough cool down for about 15 minutes. In the meantime wash, clean and slice the strawberries. Put 1 tablespoon of fruit spread aside.
Spread the sponge cake with the remaining fruit spread. Roll up from the long side. Cut into 15 slices with a sharp knife. Cover half of the slices with strawberries and brush with fruit spread put aside.
Serve on a plate. Decorate as desired with lemon balm and icing sugar. Whipped cream tastes good with it.