For the dough, put flour, 125 g sugar, salt and 1 packet of vanillin sugar in a mixing bowl. Press a depression in the middle, add egg yolk and 1-2 tbsp. water. Spread 100 g butter in flakes on the flour rim. Knead with the dough hook of the hand mixer. Knead with your hands to a smooth and supple dough
Roll out the dough into a circle (approx. 30 cm Ø) on a floured work surface. Pour into a greased tart mould (26 cm Ø) with lift-off base, sprinkled with flour. Press down the base and rim. Prick several times with a fork and chill for about 30 minutes
Mix deep-frozen blueberries and 1 tablespoon of water and let thaw. Puree with a hand blender, place in a saucepan and bring to the boil. Stir starch, 2 tablespoons of water and 1 tablespoon of sugar until smooth. Stir into the boiling blueberries, bring to the boil while stirring and allow to swell for about 1 minute. Put into a bowl and let cool while stirring
Select fresh blueberries, wash and drain well. Cream 50 g butter, 1 packet of vanilla sugar and 50 g sugar with the whisk of the hand mixer, add the eggs one by one. First stir in quark, then pudding powder
Sprinkle the dough with breadcrumbs and spread the quark mixture on top. Pour the bound blueberries into a disposable piping bag, cut off the tip. Spray the mixture as a circle at a distance of 4-5 cm from the edge. Stretch to both sides (towards the middle and the edge) with a wooden stick in a jagged shape. Spread 100 g blueberries in the middle
Bake in the preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas: level 2) for 50-60 minutes on the bottom rack. Sort the raspberries. Remove the cake from the oven, place on a cake rack and allow to cool. Remove from the tin. Mix 100 g blueberries and raspberries, spread over the cake from the middle
Waiting time approx. 15 minutes