Preheat oven to 400. Place entire bag of meatballs in pot with sauce (I also add garlic, onion powder, salt and pepper to taste) and cook over medium heat until warmed completely through, about 10 minutes. Stir as needed to keep meatballs from sticking to pot.
Once heated through remove from heat. Place meatballs in the center of a 9x13 baking dish, layer mozzarella and Italian blend cheeses over meatballs topping off with the Parmesan.
Take the slices of Italian bread and line the pan all the way around with them so that they are kind of keeping the meatballs toward the center of the pan. The bread slices will be standing up in the pan as shown in the picture.
You have creative freedom here with the bread...you can lightly butter and garlic the bread prior to placing it in the pan if you prefer or even brush lightly with olive oil and garlic. The choice is yours. I have made it plain and as noted above and all are delicious!
Place in oven and bake for approximately 25 minutes or until cheese is melted and bubbly. Remove from oven, serve and enjoy!