Preheat oven to 375°F (190°C).
Cook spaghetti in salted boiling water according to package directions until al dente.
Cut a rectangular opening in the top of each bread roll and hollow out the center, leaving a 0.5-inch shell.
In a small bowl, combine softened butter, minced garlic, and dried parsley.
Brush the interior of each hollowed bread bowl thoroughly with the garlic butter mixture.
Place bread bowls on a baking sheet and toast in the preheated oven for 5 minutes.
Drain the cooked pasta and toss immediately with marinara sauce and olive oil.
Distribute the sauced spaghetti evenly into the toasted bread bowls.
Top each bowl with a portion of shredded mozzarella and grated Parmesan cheese.
Bake for 8 to 10 minutes or until the cheese is melted and begins to brown.