Pre-heat oven to 350 degrees and line a sheet pan with parchment.
Cut loaf in half down on the long side.
Brush each side with olive oil.
Place in oven for 5 minutes to lightly toast.
Remove from oven, spread 1/4 cup of Tomato Sauce on both sides.
Arranged sliced Meatballs along one side.
Spread remaining 1/4 cup of Tomato Sauce on top of meatballs.
Arrange mozzarella slices along both sides.
Bake for 10 minutes.
Enjoy!