Step 1

Preheat oven to 375 degrees Fahrenheit.

Step 2

In a large bowl, stir together ground beef, salt, pepper, onion, bell pepper, egg, tomatoes, and oats. Place the mixture in a loaf pan. Press the surface lightly with your palm to flatten the top.

Step 3

To make the topping, combine ketchup, brown sugar, and mustard. Spread it on top of the loaf.

Step 4

Bake the meatloaf for 1 hour. Use a meat thermometer to check for doneness. The center should be at 160 degrees Fahrenheit.

Step 5

Let the meatloaf rest for 10 minutes after baking so that it holds together better while slicing.