For the shortcrust pastry, knead all the ingredients together to make a smooth firm ball of dough. Wrap the dough in plastic wrap and refrigerate for about 30 minutes. In the meantime, mix the rum raisins and the sliced almonds. Cut out the core of the apples and peel the apples.
Grease a springform pan (26 cm diameter) and sprinkle with breadcrumbs. Knead the dough briefly, roll it out and place it in the mold. Raise the edge of the dough about three centimeters so that the filling does not run out later.
First place the apples close together along the edge and then place an apple in the center of the cake. Then fill the hollowed out center of the apples with the rum raisin and almond mixture. For the cream, mix the custard powder, sugar and vanilla sugar with 0.1 l of cream until smooth.
Bring the remaining cream to a boil in a saucepan, remove from heat briefly and pour in the custard powder mixture while stirring. Bring the pudding to the boil briefly and pour over the apples, filling in the spaces a little.
Place the tart in the oven at 160 degrees convection (180 degrees bottom/upper heat) for about one hour. The surface should be brown on the apples. Let the cake cool for a day and cut it only the next day.
