Cook the pasta according to package directions until al dente. Drain and set aside.
While the pasta is cooking, heat the olive oil in a large skillet or pot over medium heat.
Add the chopped onion and cook until softened, about 3-5 minutes.
Add the minced garlic and red pepper flakes (if using) and cook for another minute until fragrant, being careful not to burn the garlic.
Pour in the crushed tomatoes. Stir in the dried basil and oregano. Season with salt and black pepper to taste.
Bring the sauce to a simmer, then reduce the heat to low and let it cook for at least 10-15 minutes, stirring occasionally, to allow the flavors to meld. For a richer flavor, you can simmer longer.
Add the cooked pasta directly to the marinara sauce and toss to coat evenly.
Serve immediately, garnished with fresh basil or parsley and grated Parmesan cheese, if desired.