Meatloaf

I made a meatloaf for dinner one night this week. I used my MIL's recipe and made a few modifications this time. I always use her recipe when I make meatloaf and generally make it as-written. But I decided to add a little extra seasoning and stuff it with cheese this week. It was really good! I'll post the recipe as-written and my changes in parentheses below.

Meatloaf

1 1/2 pounds ground beef (I only used 1 pound)
3/4 cup oatmeal
1 1/2 teaspoon salt
1 egg
1 small onion, chopped
(I also added about 1 teaspoon garlic powder and 1 teaspoon onion powder)
(I stuffed it with 1/3-1/2 cup shredded mozzarella cheese)

Sauce topping:
1/3 cup ketchup
2 Tablespoons brown sugar
1 Tablespoon mustard

Mix all ingredients together. Make sauce. Press meat mixture into loaf pan. Pour sauce over top. Bake for one hour at 350.

(I pressed half the meat in the loaf pan, pressing a small indentation in the middle. I put about 1/3-1/2 cup shredded mozzarella cheese in the indentation. Then pressed the remaining meat mixture over top.)