In a large bowl mix the meat, uncooked brown rice, 1/2 chopped onion, egg, 2 minced garlic cloves and salt. Roll the meat and rice mixture in the cabbage leaves and put them in baking dish. For the tomato sauce, sauté the onion, garlic and chopped tomatoes in a wide based pan.
Place the stuffed cabbage leaves in a baking dish, cover with the tomato sauce, add 1 cup of water and cover. Bake in the oven 350 degrees for 1 hour. Serve with a dollop of plain yogurt.