Finely grate the marzipan. Cream marzipan, fat, salt and vanilla sugar with the whisk of the hand mixer. Stir in the eggs one after the other. Mix flour and baking powder. Alternately stir in with the milk. Pour the mixture into a greased and flour-dusted square springform pan (33 x 23.5 cm) and smooth it down.
Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 60 minutes. Remove the cake from the oven and let it cool down on a cake rack. In the meantime stir the red fruit jelly powder and 5 tablespoons of water until smooth. Mix the red fruit jelly and the mixed powder. Bring to the boil while stirring and allow to cool slightly. Soak gelatine in cold water. Whip cream until stiff. Mix mascarpone, lemon juice and sugar. Squeeze the gelatine, dissolve and stir into the mascarpone drop by drop. Carefully fold in the cream. Cover the base with a baking frame. Pour in the mascarpone and red fruit jelly in strips.
Whip cream until stiff. Mix mascarpone, lemon juice and sugar. Squeeze the gelatine, dissolve and stir into the mascarpone drop by drop. Carefully fold in the cream. Cover the base with a baking frame. Pour in the mascarpone and red fruit jelly in strips. Chill for at least 2 hours. Cut the cake into 18 pieces and sprinkle with pistachios
waiting time approx. 2 hours