Bring a large pot of salted water to a boil. Add the spaghetti and cook according to package instructions until al dente, about 9 to 11 minutes. Drain and set aside.
While the pasta cooks, heat olive oil in a large skillet over medium heat. Add the chopped onion and sauté until translucent, about 5 minutes.
Add the minced garlic to the skillet and cook for 1 minute until fragrant, stirring frequently to avoid burning.
Pour in the crushed tomatoes, then stir in dried oregano, dried basil, salt, black pepper, and red pepper flakes. Bring the sauce to a simmer and cook for 15 minutes, stirring occasionally.
Stir the grated Parmesan cheese and chopped fresh basil into the sauce. Remove from heat and keep warm.
Preheat the oven to 375°F (190°C).
Slice the Italian bread in half lengthwise. In a small bowl, combine the softened butter, minced garlic, and chopped parsley.
Spread the garlic butter mixture evenly over both bread halves.
Place the bread halves on a baking sheet, buttered side up, and bake for 10 to 12 minutes or until the bread is golden and crispy around the edges.
Cut the garlic bread into slices.
Toss the cooked spaghetti with the tomato sauce until well coated.
Serve the pasta topped with extra grated Parmesan and a sprinkle of fresh basil if desired, alongside the warm garlic bread.