Cut the onion head finely and fry it in a little oil until lightly golden. Soak the breadcrumbs in the milk, add the egg yolk, stir until uniform and leave it for 15 minutes. Then add them to the minced meat, season with black pepper, salt and mix.
Form meatballs the shape and size of a large walnut. Fry them in heated oil in a pan with sloping walls, placing them in carefully so that they retain their spherical shape. Turn them over by shaking the pan and fry until they get an even golden color.
Usually, these are served with mashed, fried, or boiled potatoes.