Put flour, 350 sour cream and butter in flakes in a 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 45 minutes
Mix 350 g sour cream with horseradish and season with salt. Cut salmon slices into strips. Roast pine nuts in a pan without fat until golden brown, take them out and let them cool down. Wash the dill, shake dry and chop coarsely
Roll out the dough on a floured work surface to a thickness of approx. 1/2 cm, cut out 14 circles (approx. 15 cm Ø) and knead the rest again and again. Place the circles next to each other and put a blob of sour cream on each, leaving a rim of about 3 cm all around. Spread the salmon strips, pine nuts, capers and dill on top. Press the edges of the dough firmly together over the filling
Place 7 pieces on each of two baking trays lined with baking paper. Whisk the egg yolks and 1-2 tsp. cold water. Spread a thin layer on the parcel. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) one after the other for about 30 minutes. Take out, serve hot or cold