Peel, halve and core apples and sprinkle with lemon juice. Coarsely grate the marzipan and stir the poppy seed filling until smooth. Cream soft fat, sugar, vanilla sugar, lemon peel and salt with the whisk of the hand mixer. Stir in the eggs one by one, alternating with the cornflour. Stir in sour cream.
Mix flour and baking powder and stir in briefly. Pour the dough into a greased, breadcrumbed pan of the oven (32 x 39 cm; at least 3.5 cm deep) and smooth it down. Place the apples on the dough with the curvature downwards. Pour poppy seed mixture into the apple depressions with 2 teaspoons. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 45-50 minutes. Take the cake out of the oven. Stir jam until smooth, spread thinly on the hot cake. Let the cake cool down, cut into pieces. Arrange on a plate and decorate with apple slices and slices.
Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 45-50 minutes. Take the cake out of the oven. Stir jam until smooth, spread thinly on the hot cake. Let the cake cool down, cut into pieces. Arrange on a plate and decorate with apple slices and slices. Whipped cream tastes good with it