1Heat oven to 400°F. Generously grease rectangular baking dish, 13x9x2 inches. Cook ground beef and onion in 10-inch skillet over medium heat, stirring occasionally, until beef is brown; drain. Stir in soup, vegetables and milk.
2Stir Bisquick mix and water in baking dish until moistened; spread evenly. Spread beef mixture over batter. Sprinkle with cheese.
3Bake 30 minutes.