In lukewarm milk put sugar and yeast and let it rise. Sieve the flour into a bowl. Add the egg and egg yolks, effervescent yeast, salt and melted butter. Knead the dough until smooth and separated from the walls of the vessel. Form a ball and let it rest covered bowl at least an hour, hour and a half while doubling the volume. At the end of souring prepare the ingredients for the filling - cut into cubes or optional. Knead lightly dough again and divided into about 16 equal parts (I do so - share the first two, then each half into two again, and again and again until they are 16). Formed into balls that are rolled or stretched or upsetting flat buns. Put it in the middle of filling and closes as bundle. Placed at a distance from one another in a buttered baking dish with the closed side down. Leave to rise again until fill. When done Spread top with beaten egg and sprinkle with coarse salt. Bake in a preheated 180-200 C oven for about 30 minutes until nice golden color.