Peel the onions and cook them whole for 3 - 4 minutes in boiling water. Then cool them under cold water, drain them, hollow them out, salt and pepper them. Put the hollowed-out mass aside.
Soak the toasted bread in milk, squeeze it and tear it into small pieces with a fork. Mix the minced meat with the bread pieces, season with salt, pepper and sweet paprika and grill seasoning. Fill the onions with the mixture.
Grease a baking dish, spread the chopped hollowed-out meat on the bottom and the onions on top. Place a flake of butter on top of the onions and make a cap with the grated cheese.
Bake the onions in an oven preheated to 180°C until the cheese is brown. Serve the onions together with the stewed juices.