For the short pastry, knead 300 g flour, baking powder, 100 g sugar, vanilla sugar, egg and 175 g cold butter in pieces first with the dough hooks of the mixer, then with your hands to a smooth dough.
Cover and chill for about 30 minutes.
In the meantime peel the apples, quarter them, remove the core and cut them into small cubes. Bring to the boil with 100 ml water, lemon juice, 75 g sugar and cinnamon. Simmer covered for 6-8 minutes. Drain very well and let it cool down a bit.
Preheat oven (electric cooker: 175°C/circulating air: 150°C/gas: level 2). Grease a springform pan (approx. 26 cm Ø). Roll out approx. 3/4 of the dough on a little flour until round (approx. 34 cm Ø). Put the dough into the springform pan, pressing the rim about 4 cm high.
of a fork several times. Pre-bake in the hot oven on the lowest shelf for about 12 minutes.
In the meantime roll out the remaining dough on a little flour until it is round (approx. 26 cm Ø) and prick several times with a fork. Remove the mould from the oven. Sprinkle the base with breadcrumbs and spread the apples on top.
Place the dough lid on top and carefully press down the rim. Continue baking at the same temperature on the lowest rack for 45-50 minutes. Let the cake cool down.
Stir icing sugar and 3 tablespoons of water until smooth. Spread evenly on the cake. Leave to dry. Whipped cream tastes good with it.