Mix flour and baking powder and sieve into a bowl. Add sugar, vanillin sugar, butter in small pieces, crème fraîche and egg and knead to a smooth dough. Divide the dough in thirds. Roll out 2/3 on the floured work surface to the size of a baking tray (32 x 39 cm), wrap on the cake roll and roll off again on the greased baking tray. Pull the dough up by the edge, prick several times with a fork. For the topping, finely chop the apricots in the universal chopper. Mix jam, liqueur and apricots.
Spread the apricot mixture on the dough. Roll out the remaining dough to a rectangle (approx. 45 x 20 cm). Whisk egg yolk and milk, spread on the rectangle. Cut lengthwise into strips about 1 cm wide, place the strips diagonally crosswise at about 3 cm intervals on the apricot mixture. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 20 minutes. Let the pastry cool down on a cake rack. Cut into rectangles (approx. 4 x 6 cm)
1 hour waiting time