Put 250 g flour, hazelnuts, 125 g butter in small pieces, 75 g sugar, 1 pinch of salt and 1 egg in a bowl. Knead first with the dough hooks of the hand mixer, then briefly with your hands to a smooth dough. Grease a springform pan (26 cm Ø) and dust with flour. Spread the dough evenly in the form, pressing the rim about 4 cm high. Prick the base several times with a fork, chill the baking tin for about 30 minutes
Cut the vanilla pod lengthwise and scrape out the pulp. Put 1 teaspoon butter, milk and vanilla pod in a pot and bring to the boil. Remove the pod. Mix 1 heaped tbsp. flour, 150 g sugar and 1 pinch of salt and stir into the milk. Bring to the boil again, pour into a bowl and allow to cool for about 5 minutes (if lumps have formed, finely puree the mixture with the chopping stick). Whisk vanilla pulp and 3 eggs. Stir in 3 tablespoons of hot cream, then stir into the rest of the cream
Cover the bottom of the springform pan with baking parchment, add dried peas for blind baking. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 15 minutes. Take out the tin, remove the dry peas and baking paper. Bake again at the same temperature for about 5 minutes. Remove the base
In the meantime, wash the apples, grate them dry and core them with an apple corer. Knead marzipan, rum raisins, ground cinnamon and 1 teaspoon sugar. Fill apples with it. Cut the cinnamon sticks in half crosswise and stick them into the apples as "stems". Set apples aside
Spread the apples in the mould (if necessary, cut the bottom of the apples straight so that they stand better) Fill up with icing and bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 1-1 1/4 hours until the egg mass has set. Finally cover with aluminium foil if necessary. Remove the cake, let it cool down and remove from the tin
Waiting time approx. 20 minutes