01 - Bring a large pot of salted water to a boil. Cook pasta until al dente according to package directions. Reserve ½ cup pasta water, drain pasta, and set aside.
02 - Heat olive oil in a large skillet over medium heat. Add finely diced onion and sauté until soft and translucent, about 3 to 4 minutes.
03 - Stir in minced garlic and cook for 1 minute until fragrant.
04 - Add crushed tomatoes, tomato paste, dried oregano, salt, pepper, and chili flakes if using. Simmer for 5 to 7 minutes, stirring occasionally.
05 - Reduce heat to low and pour in heavy cream. Simmer gently for 2 to 3 minutes until the sauce thickens slightly.
06 - Stir in grated Parmesan cheese until fully melted and sauce is velvety.
07 - Add cooked pasta to skillet, tossing to coat evenly. Use reserved pasta water as needed to achieve desired sauce consistency.
08 - Fold in chopped fresh basil. Taste and adjust seasoning with salt and pepper as needed.
09 - Serve immediately, garnished with additional basil and Parmesan cheese if desired.