Boil the peeled onions for 15 minutes in salted water. Take them out, carefully remove the insides and cut them into small pieces. Fry the garlic clove in the oil until golden.
Remove it and in the same oil, fry the mushrooms for about 2 minutes. Add the minced meat, fry for 2 minutes and remove from the heat. Add the onion insides, spices and eggs to the mince. Fill the onion heads with this mixture.
On each, sprinkle breadcrumbs. Place them in an oven dish, add a little oil and a cup of hot water. Bake in a preheated 356°F (180 °C) oven for about 50 minutes (until golden brown).