Put the yeast and sugar to bubble with a little warm water. Sift the flour and mix it with the salt. Make a well and add the beaten eggs with yoghurt and vinegar. Add the effervescent yeast and milk, knead a smooth and elastic dough.
Allow to rise until doubled in volume. Divide the dough into 2 parts. Roll out each into a thin crust. By using a glass, cut out circles. Place 3 slices on top of one another, slightly overlapping them. Cut them down the middle.
Put a piece of sausage and cheese in each part, twist them into a roll, and stack two rolls each in buttered cups (I used a muffin tray).
Brush with egg yolk, leave them to rise for 20 minutes. Bake for 25-30 minutes. Spread the finished rolls with butter and wrap them with a clean cloth.