Clean and wash the gooseberries and let them drain well in a sieve. Pour cream into a mixing bowl. Wash 1 cup and dry. Add 1 cup of sugar, vanillin sugar and salt to the cream and whisk it with the whisks of the hand mixer until half stiff.
Stir in the eggs bit by bit. Mix flour and baking powder, sieve onto the cream egg mixture and stir in. Pour the dough onto a well greased baking tray (32x38 cm) sprinkled with flour and smooth it down.
Finely grate the marzipan on top. Pre-bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 10 minutes. Then spread gooseberries evenly on top. Sprinkle with almond slivers and 1/2 cup of sugar.
Bake at the same temperature for another 25-30 minutes. Remove from the oven, place on a rack and allow to cool. Cut into pieces. Serve with whipped sour cream.