Meatball Sub Casserole

Preheat oven to 425 degrees F (220 degrees C).

Heat garlic bread with spread side up on a baking sheet in the preheated oven until warm and golden brown, 10 to 12 minutes.

Set aside to cool.

Reduce oven temperature to 350 degrees F (175 degrees C).

Bring spaghetti sauce to a boil in a large pot.

Place frozen meatballs into sauce.

Reduce heat to low and simmer until meatballs are heated through, about 20 minutes.

Tear garlic bread into bite-size pieces and spread into bottom of a 9x13-inch baking dish.

Pour spaghetti sauce and meatballs over garlic bread, coating bread with sauce and distributing meatballs evenly.

Spread mozzarella cheese over top in a layer, followed by a layer of Parmesan cheese.

Bake casserole until cheese has melted, 20 to 25 minutes.