Cheeseburger Muffins

1/2 pound ground beef 

1 small onion, finely chopped

2-1/2 cups all-purpose flour

1 tablespoon sugar

2 teaspoons baking powder

1 teaspoon salt

3/4 cup ketchup

3/4 cup milk

1/2 cup butter, melted

2 large eggs

1 teaspoon prepared mustard

2 cups (8 ounces) shredded cheddar cheese

Cook ground beef and onion over medium heat until meat is no longer pink; drain. In a large bowl, combine the flour, sugar, baking powder and salt; set aside. In another bowl, combine the ketchup, milk, butter, eggs and mustard, and stir into the dry ingredients just until moistened. Fold in the beef mixture and cheese. Fill greased muffin cups three-fourths full. Bake at 425° for 20-25 minutes or until a toothpick comes out clean. Cool for 5 minutes before removing from pans to wire racks. Serve warm. Refrigerate leftovers. Makes about 2 dozen.  (You can also make these in mini muffin pans.  Bake for 15-18 minutes.  You should get about 5 dozen.)