Preheat oven to 350 degrees F (175 C)
Combine egg, milk, cheese, oats, and salt. Add ground beef, mixing well, and form into either miniature meatloaves. Place these in a lightly greased 9x13 inch baking dish.
In a separate bowl, combine the ketchup, brown sugar, and mustard. Stir thoroughly and spread over each meatloaf.
Bake, uncovered, for 45 minutes.