Preheat oven to 375°.
Place tomato, onion, pepper and garlic on baking sheet, sprinkle with oregano, salt and pepper.
Drizzle with olive oil and mix.
Roast, uncovered, about 45 minutes until tender and beginning to brown.
Place roasted vegetable mixture and fresh basil in food processor or blender. Blend until smooth.
Bring large pot of water to boil. Add spaghetti and cook according to package directions. Drain.
Serve topped with warmed sauce. Sprinkle with additional Parmesan cheese if desired.