Mix beef, onion, salt, pepper, cinnamon and egg together. Set aside. Peel hard boiled eggs and cut in half crosswise. Take 2 heaping tablespoons of beef mixture and cover the egg half. Form a meatball with the egg in the center. Heat oil in skillet and fry meatballs for 4 minutes. Drain and serve with lemon wedges. Can be served over rice or couscous.