How to make
Melt the butter and let it cool. Beat the eggs, add the butter, stir until homogeneous. Sift the flour, make a well in the middle, add the salt, vinegar and egg-butter mixture.
Heat the milk slightly, add the sugar and dissolve the yeast. Leave it for 15 min. to bubble. Knead a dough, while adding from the yeast until fully absorbed and form a smooth, soft dough.
If needed, add a little more flour when kneading. Cover with foil and leave it in a warm area to rise for 1 hour.
Divide the ready dough into 7 equal parts, form each one into a round ball. Smear a deep, round tray with a little butter, arrange the dough balls in it some distance apart from one another.
Cover with a clean towel and let it rise for another 30 min. until increased in volume. Melt the butter that you'll be smearing with and let it cool. Mix it with the yolk, beat and smear the risen loaf with this mixture.
Bake in a preheated 320°F (160 °C) oven for about 1 hour until you get a golden crust.