Preheat oven to 350 degrees F. Line a large
baking sheet with aluminum foil and spray with
nonstick cooking spray. In a large bowl,
combine egg, milk, oats, Italian seasoning,
salt and pepper; stir until well combined. Let
sit for 5 minutes to allow oats
to absorb liquid. Add onion and ground beef,
mixing well. Grabbing baseball-sized portions,
form mixture into six small meatloaves (the
loaves will shrink slightly as they bake).
Stuff each portion with a string cheese half,
forming meat mixture around cheese. Place onto
prepared baking sheet. In a separate small
bowl, stir together ketchup, brown sugar and
mustard. Spoon evenly over each loaf. Bake
uncovered for 45 minutes.