For the apple sheet cake, first mix all the ingredients together for the shortcrust pastry and quickly knead into a dough. Wrap the dough in plastic wrap and let it rest in a cool place for half an hour.
Wash and peel the apples and cut them into thin slices. Put the apple slices in a pot with the apple juice, white wine and sugar and steam.
For the pudding, make a pudding from the apple juice, white wine and pudding powder according to package instructions.
Strain the steamed apple slices and mix with the pudding.
Preheat the oven to 180 degrees top and bottom heat.
Roll out the dough on a lightly floured baking paper, place it on the baking tray with the baking paper and press up an edge. Spread the apple custard filling evenly on the short pastry base.
Bake the apple pie in the preheated oven for about 40 minutes. Then allow to cool completely – preferably overnight in the refrigerator.
Whip the GUMA Pâtisserie cream until stiff, pipe it onto the cake using a piping bag and chill again. Sprinkle apple sheet cake with ground cinnamon before serving.