Warm the milk lukewarm in a saucepan. Stir in sugar and yeast. Put the flour in a mixing bowl, pour the yeast milk into the middle and cover with a little flour and let rise for about 15 minutes.
Separate the egg white from the yolk. Add butter, quark, egg white and spices to the pre-dough and knead for at least 5 minutes to form a smooth dough. Cover the dough and let it rise for about 1 hour.
Knead the dough briefly and roll it out into a circle on a floured work surface. Using a dough card, cut into 8 equal triangles or pizza pieces. Roll up the triangles from the long side and bend them into a crescent. Place on a baking sheet lined with baking paper and let rise for 15 minutes. Preheat the oven to 180 degrees.
Whisk the egg yolk with 1 tablespoon of milk and brush the croissants with it before baking. Bake for about 20 minutes. Let cool on a wire rack.