Gently remove leaves from cabbage head and blanche in boiling water until tender enough to handle. Drain and cool.
Combine ground beef, onion, garlic powder, egg, rice, salt and pepper. Mix well.
Place a 1/2 a fist sized ball of meat in the middle of a cabbage leaf. Roll, tucking in sides. Place in a large casserole dish. Continue until all of the meat is used up. Lay remaining cabbage leaves over rolls.
Pour tomatoe sauce over cabbate rolls. Cover with foil and bake at 350 degrees for approx. 1 hour.