Defrost the raspberries in a bowl at room temperature. Place puff pastry slices next to each other and defrost. Whisk the egg yolks and spread on the puff pastry slices. Sprinkle 1 slice each with sugar crystals, pistachios and chocolate sprinkles. Cut the slices lengthwise into 9 strips and turn each strip into a cord. Line a baking tray (32 x 39 cm) with baking paper.
Place puff pastry sticks on top. Bake in the preheated oven (electric cooker: 225 °C/ convection oven: 200 °C/ gas: level 4) for 5-8 minutes. Remove and let cool on a cake rack. Stir quark, milk and vanilla sugar until smooth, fold in raspberries. Pass the raspberry-vanilla quark to the puff pastry sticks
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