BISQUICK'S IMPOSSIBLE CHEESEBURGER PIE

1 lb ground beef

1 1/2 cups chopped onion
1/2 tsp salt
1/4 tsp pepper
1 1/2 cups milk
3/4 cup Bisquick baking mix
3 eggs
2 tomatoes, sliced
1 cup shredded Cheddar or process American cheese

Heat oven to 400 degrees. Grease pie plate, 10 x 1 1/2-inches. Brown beef and onion; drain. Stir in salt and pepper. Spread in pie plate. Beat milk, baking mix, and eggs until smooth, 15 seconds in blender or on high 1 minute with hand beater. Pour into plate over hamburger. Bake 25 minutes. Top with tomatoes and sprinkle with cheese. Bake until a knife inserted in center comes out clean, another 5 to 8 minutes. Cool 5 minutes.

Note: For high altitudes, increase first baking time from 25 to 30 minutes.