01 - Fill a large pot with water, season generously with salt, and bring to a robust boil. Cook pasta according to package directions until al dente. Drain, reserving 1/2 cup pasta water.
02 - In a large skillet, warm olive oil over medium heat. Add chopped onion and cook until translucent, about 3 to 4 minutes.
03 - Stir in minced garlic and cook for 1 minute, just until fragrant.
04 - Add crushed tomatoes and tomato paste, stirring well. Cook for 5 to 7 minutes until sauce reduces slightly and thickens.
05 - Reduce heat to low and add heavy cream, Parmesan cheese, sugar if desired, salt, and black pepper. Simmer for 2 to 3 minutes until sauce is creamy and heated through.
06 - Add cooked pasta to the sauce in the skillet. Gradually add reserved pasta water for a smooth, silky sauce. Toss thoroughly to coat each piece.
07 - Mix in chopped basil just before serving to preserve fresh flavor.
08 - Portion immediately onto plates, garnishing with additional basil and grated Parmesan cheese.