Put all ingredients except butter in a mixing bowl and knead until combined.
Then add the butter in pieces and knead into a smooth dough. Knead for at least 5 minutes.
Cover and leave to rise in a warm place for about 1 hour.
Divide the dough in half and form into balls.
Roll out one ball on a lightly floured work surface.
Brush with half of the melted butter.
Divide into 8 pieces. (like pieces of cake, for example, with a pizza cutter).
Roll up the pieces from the wider side. If you like, you can make two long cuts in the top of the dough.
Shape like a croissant.
Place on a baking tray with baking paper.
Brush with yolk-milk mixture.
Sprinkle with hail sugar.
Leave to rise for another 20 minutes.
Bake in the preheated oven at 180° for about 14 minutes.