Cheesy Meatball Subs

These were so incredibly easy and I can't believe I never thought about making them sooner. A co-worker mentioned making these, and shortly after I ran across a recipe for them. This is similar to the recipe I found, though not exact, because really, it's a 'play it by ear' kind of thing.
Here are my ingredients:

• 2 cups spaghetti sauce
• 4 tablespoons grated parmesan cheese
• 24 ounces frozen meatballs
• 8 crusty buns (I just used a package of 'sub' buns, but something crustier would be better, like a mini Italian loaf or something)
• shredded mozzarella cheese

Combine spaghetti sauce and parmesan cheese in a large skillet. Add meatballs. Stir gently to coat. Bring to a boil.

Simmer 8 minutes or so until meatballs are heated through. Stir occasionally so that they all get heated!

Spoon onto buns and sprinkle with cheese.

This recipe could easily be cut in half or adjusted to how ever many sandwiches you need.