Add cooked spaghetti to the saucepan and toss to coat with the sauce. Season with salt and pepper to taste.
Remove the bread from the oven and top each half with shredded mozzarella cheese.
Return the bread to the oven and bake for an additional 5-7 minutes, until the cheese is melted and bubbly.
Cut the bread into slices and serve alongside the spaghetti.
