For the cheese scones, mix flour, baking powder, a little sugar and salt. Add sour cream, crème fraîche, cheese and herbs to flour mixture and knead until ingredients are well combined.
Roll out on a floured work surface to about 1 cm thick. Cut out circles 6 cm in diameter. Place on a baking sheet lined with parchment paper. Roll out and cut out the leftovers again.
Mix egg yolk and milk, brush the circles with it. Bake the cheese scones in a preheated oven at 160 degrees on the 2nd rack from the bottom for about half an hour.