For the shortcrust pastry, put 300 g flour, 150 g sugar, 1 packet vanillin sugar, salt, egg, 150 g fat in flakes and 2 tablespoons water in a mixing bowl. Knead first with the dough hooks of the hand mixer, then with your hands to a smooth dough. Wrap in foil and chill for about 30 minutes
Meanwhile put 100 g flour, 50 g sugar, salt, 1 sachet vanillin sugar and 75 g fat in flakes into a mixing bowl, work into fine crumbles with your hands
Halve the shortcrust pastry. Wrap one half in foil again and chill. Roll out the remaining dough thinly on a floured work surface. Cut out approx. 42 triangles with a triangular cutter with wavy edge (side length 6.7 cm). Knead, roll out and cut out the rest of the dough again and again
Place on 2 baking trays lined with baking paper. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) one after the other for approx. 7 minutes. Remove from the oven, place on a cake rack and let cool.
Roll out the second half of the dough thinly on a floured work surface and cut out approx. 42 triangles of the same size as described above. Place on 2 baking trays lined with baking paper. Whisk the egg yolk and 1 tbsp. water. Brush the dough triangles with the mixture and spread the crumbles evenly over them.
Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for approx. 10 minutes one sheet at a time. Remove from the oven, let cool on a cake rack
Stir the jam until smooth. Spread simple triangles thinly with jam. Place crumble triangles on top. Dust with icing sugar
Waiting time 1 hour