Preheat oven to 350 degrees F and spray a loaf pan with cooking spray.
In a bowl, combine ground beef, bread crumbs, milk, and egg. Mix until ingredients are evenly combined.
Place beef mixture into loaf pan and press down to evenly spread over bottom of pan.
In a small bowl, mix together ketchup, brown sugar, and mustard.
Pour over meat and spread evenly.
Bake for 50 to 55 minutes, or until done. Enjoy!