Mix flour, sugar and salt.
Add butter in pieces and crumble.
Add the egg and knead into a dough.
Roll out half of the dough on a floured work surface.
Cut out a 26cm diameter circle from the dough. Place on a baking paper and then in the fridge.
Roll out the rest of the dough and place in the 26cm springform pan. Form a high rim. Place in the fridge.
Peel and core the apples and cut into small pieces or flakes.
Put the apple pieces in a pan with the sugar and cinnamon.
Cover and steam briefly.
Mix the apple juice with the custard powder and stir into the apples.
Mix in the raisins and almond flakes and leave to chill briefly.
Pour the apple filling into the springform pan.
Press down the rim.
Place the pastry sheet on top and press down a little.
Brush with milk.
Prick with a fork.
Bake in the preheated oven at 200° C for about 50 minutes.
Mix powdered sugar with milk.
Spread on the finished cake.
Leave to cool.