Defrost the raspberries. Meanwhile, separate the eggs. Mix egg yolks, 1 1/2 tablespoon cold water, vanillin sugar and lemon peel. Stir in flour. Beat 6 egg whites until stiff. Finally, pour in 3 tablespoons of sugar.
Carefully fold the egg yolk mixture into the beaten egg white. Pour the cloudy mixture into 2 greased, ovenproof casseroles (300 ml capacity each) and bake in a preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas: level 2) for 12-15 minutes.
In the meantime, puree the raspberries and 3 tablespoons of sugar and pass through a sieve. Wash the mint and shake dry. Remove meringue gratin from the oven and dust it thickly with icing sugar. Decorate with mint.
Add the raspberry sauce.