Roll out the dough into a rectangular sheet, smear it with butter. Sprinkle finely chopped ham and grated cheese on top. Roll it up into a loose roll so that there's air and let it double its volume.
Smear a cake form with oil and sprinkle it with flour or use a tray with a cup in the middle. Put the roll in the form, connect the ends together.
With a knife or scissors, make cuts down to the bottom of the form. Beat and egg yolk and smear it with it, sprinkle sesame and poppy seeds. Bake in a preheated 356°F (180 °C) oven until reddened.