Place cabbage in boiling, salted water and cook for 10 minutes. Drain and cut out center to free the leaves. Saute onions in oil until golden brown. Combine onions, meat, seasonings, parsley, rice and half the canned tomatoes, mixing well. Place a generous portion of meat mixture on the base of the cabbage leaf, turn up base, fold in sides and wrap firmly. Place rolls together, seam side down (to keep from unwrapping) in a dutch oven or deep pan. Pour remaining tomatoes and tomato sauce over top, add more seasoning if needed. Simmer gently for 1 1/2 hours, partially covered. Serve hot with a side dish of sour cream or yogurt.