1Heat oven to 350ºF. In 12-inch nonstick skillet, cook beef and onion over medium heat 8 to 10 minutes, stirring occasionally, until thoroughly cooked; drain well. Stir in frozen vegetables, mushrooms, tomatoes, gravy, chili sauce, basil and pepper. Heat to boiling. Reduce heat; cover and simmer about 10 minutes or until vegetables are tender.
2While beef mixture is simmering, make potatoes as directed on pouch, using water, milk and butter. Let stand 5 minutes.
3Spoon beef mixture into ungreased 8-inch square (2-quart) glass baking dish or 2-quart casserole. Spoon potatoes onto beef mixture around edges of dish. Sprinkle with cheese.
4Bake uncovered 25 to 30 minutes or until potatoes are firm and beef mixture is bubbly.