Preheat your oven to 350°F (175°C).

Cut the tops off the round bread rolls and hollow out the insides, leaving about half an inch of bread for support.

In a small bowl, mix melted butter, minced garlic, and chopped parsley. Brush the mixture inside and outside of the hollowed rolls.

Place the prepared bread bowls in the oven and bake for 10 minutes until lightly golden.

Cook the spaghetti in salted boiling water until al dente, then drain and drizzle with olive oil.

Heat the marinara sauce in a medium saucepan over medium heat, adding any optional ingredients, and simmer for 10-15 minutes.

Stir the cooked spaghetti into the heated sauce, then add diced mozzarella and grated parmesan, mixing thoroughly.

Fill each toasted bread bowl with the spaghetti mixture and top with remaining cheese.

Increase the oven temperature to 375°F (190°C) and bake filled bowls for 12-15 minutes until cheese is bubbly.

Allow to cool for 3-5 minutes, garnish with parsley, and serve warm.