Grease a springform pan (26 cm Ø) and dust with flour. Peel, halve and core apples. Cut the curvature of the apple halves several times. Sprinkle apples immediately with lemon juice.
Preheat oven (electric cooker: 175°C/circulating air: 150°C/gas: level 2). Whisk butter, sugar, vanilla sugar and 1 pinch of salt with the whisk of the hand mixer for 3-4 minutes until creamy. Stir in eggs one at a time.
Sift flour and baking powder over it, stir in briefly.
Smooth the dough in the mould, place the apple halves on the dough with the curvature facing upwards. Bake in a hot oven for 40-45 minutes.
Stir the jam until smooth. Spread the apples on the cake about 10 minutes before the end of the baking time. Sprinkle with flaked almonds and bake until done. Let the apple cake cool down. Dust with icing sugar.
Whipped cream tastes good with it.