This is the most delicate apple cake that literally melts in your mouth. It’s amazingly tasty, fresh and unusual.
- For the dough, mix the sifted flour with the baking powder and the grated (or finely chopped) cold butter. Grind the mixture into crumbs. Whisk the egg with sugar, and add the mix to the dough. Knead until homogeneous.
- Wrap the dough in foil, and refrigerate it for 1 hour.
- Divide the dough into 6 pieces. Roll each piece of dough into a layer on the floured parchment.
- Stick the dough with a fork, and bake it in the oven preheated to 200C (392F) for 5 to 7 minutes until golden. Cut the hot cake layers with a 16 cm (6.3 inch) ring.
- Peel the apples; cut them into slices, and sprinkle with the lemon juice. Place the apples in a heavy-bottomed saucepan, and add a little water; simmer for 5 minutes under a closed lid.
- Add the sugar, and simmer over a low heat for 15 minutes until cooked. Grind the hot apples with a blender until puree, and immediately add the sour cream and the butter.
- Stir until smooth, and add the vanilla sugar; cool the custard, and place it in the fridge for 3 hours.
Whip the cooled custard with a mixer, and grease the cooled cake layers with it. Caution, the cake layers are very fragile!
Assemble the cake, and coat the sides and the top with the custard; decorate the cake with crumbs from the cake layers scraps. Place the cake in the fridge overnight.