This comes from my Taste of Home Ground Beef Cookbook, it's a must-have cookbook that I use ALL the time. The kids LOVED this casserole, which is rare, and it disappeared so fast that I didn't even get a picture. I will take one next time I make it.
1 pound ground beef
1 large onion, chopped
1/2 cup chopped green pepper
2 tablespoons ketchup
1/2 teaspoon ground mustard
1/4 teaspoon salt
1-1/2 cups cooked long grain rice
1-1/2 cups shredded cheddar cheese
1 can (10 3/4 oz) condensed cream of mushroom soup
1 cup milk
1 teaspoon Worcestershire sauce
2 cups corn flakes, coarsely crushed
3 tablespoons butter or margarine, melted
In a skillet, cook beef, onion, and green pepper over medium heat until meat is no longer pink. Add the ketchup, mustard and salt. Mix well. Transfer to a greased 2-qt baking dish. Top with cooked rice. In a bowl, combine the cheese, soup, milk, and Worcestershire sauce. Pour over rice. Combine cornflakes and butter, sprinkle over top. Bake, uncovered, at 375 degrees for 35 minutes or until heated through.