01 - Bring a large pot of salted water to a boil. Cook pasta until al dente according to package instructions. Reserve ½ cup of pasta water, then drain and set aside.
02 - Heat olive oil in a large skillet over medium heat. Add diced onion and cook 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, oregano, salt, pepper, and chili flakes if using. Simmer for 5 to 7 minutes, stirring occasionally.
05 - Reduce heat to low. Pour in heavy cream and simmer gently for 2 to 3 minutes until sauce thickens slightly.
06 - Stir in grated Parmesan cheese until fully melted and sauce is creamy.
07 - Add cooked pasta to the sauce and toss to coat evenly, adding reserved pasta water as needed to achieve desired consistency.
08 - Stir in chopped fresh basil. Adjust seasoning to taste.
09 - Plate immediately and garnish with additional basil and Parmesan cheese if desired.