Quickly mix flour, fat in flakes, 3 tablespoons icing sugar, 1 egg and 3 tablespoons cold water with the dough hooks of the hand mixer to a smooth dough. Cover the shortcrust pastry and chill for about 30 minutes.
In the meantime, grease a tart mould with a removable base (26 cm Ø) and dust with flour. Roll out the dough on a well floured work surface (30 cm Ø) and place it in the tin, lifting up the edges.
Sprinkle the bottom with breadcrumbs. Mix créme fraîche, 40 g sugar, vanillin sugar, 2 eggs and pudding powder. Pour the mixture onto the cake base and smooth it down. Bake the tart on the lower level in the preheated oven (electric oven: 200 °C/ convection oven: not suitable/ gas: level 3) for 35-40 minutes.
Take the tart out of the oven and place it on a cake rack and let it cool down for about 1 hour. In the meantime, wash and clean the strawberries and, depending on the size, halve or quarter them. Sort the currants, wash if necessary and remove from the panicles.
Select raspberries, blueberries and blackberries, wash if necessary. Sprinkle the berries with 1 tablespoon of sugar and leave to stand for about 30 minutes. Remove the tart from the mould and cover with berries. Sprinkle with berry stock and dust with 1 tablespoon of icing sugar.