Grease a springform pan with a tube bottom insert (26 cm Ø; approx. 8 cm high) and dust with flour. Peel, halve and core apples. Sprinkle with lemon juice. Cream butter, sugar, vanillin sugar and 1 pinch of salt. Stir in the eggs one by one. Mix flour and baking powder and stir in portions
Cut the dough in half. Mix nuts and cinnamon, stir with milk under 1 half of the dough. One after the other, fill half nut dough, half light-coloured dough, then the rest nut dough and the rest light-coloured dough into the mould, smooth it down. Place apples on top with the curvature downwards and press them slightly into the dough. Bake in the preheated oven (electric cooker: 175 °C/circulating air: 150 °C/gas: level 2) for approx. 50 minutes. Cool in the tin for about 10 minutes. Remove from the mould, let cool completely
Roast nut flakes without fat, cool. Mix icing sugar and Calvados to a thin icing. Spread the cake surface with it. Sprinkle with nut flakes. Leave to dry