The recipe is enough for a springform pan with a diameter of 26 cm.
Knead the flour with the butter, 175 g sugar, an egg and the grated zest of a lemon. Cover and chill the dough for 2 hours.
Peel and quarter the apples and remove the core. Cut the apples into thin wedges and mix with the lemon juice. Add the raisins, 50 g sugar and the cinnamon to the apples.
Preheat the oven to 200 degrees (top / bottom heat).
Roll out the dough and use it to line the base and edge of a springform pan. Prick the pastry base several times with a fork and spread the apple mixture on top. There is left over dough, cut it into narrow strips to decorate the cake with a grid (similar to a Linzertorte).
Whisk 2 eggs with milk, 1 tablespoon sugar and custard powder. Pour over the apples. Place the strips of dough on top like a grid. Bake the cake on the 2nd rack from the bottom for 50-60 minutes, first let it cool down in the tin and then place it on a wire rack to cool completely.