01 - Bring a large pot of salted water to a rolling boil. Add pasta and cook until al dente according to package directions. Reserve 1/2 cup of the starchy cooking water before draining thoroughly.
02 - Heat olive oil in a large skillet over medium heat. Add chopped onion and cook 3-4 minutes until translucent and softened. Add minced garlic and stir constantly for 1 minute until fragrant, being careful not to brown.
03 - Stir in tomato paste and cook for 1 minute to deepen flavor. Pour in crushed tomatoes, sugar, oregano, and red pepper flakes if using. Season generously with salt and pepper. Bring to a gentle simmer.
04 - Reduce heat to maintain a steady simmer and cook uncovered for 8-10 minutes, stirring occasionally. The sauce should thicken slightly and develop a rich, concentrated flavor.
05 - Lower heat to gentle setting. Pour in heavy cream while stirring continuously. Add grated Parmesan cheese and stir until melted and fully incorporated. Cook for 2 minutes until sauce becomes velvety smooth.
06 - Add drained pasta directly to the skillet. Toss thoroughly to coat every piece with sauce. Add reserved pasta water a tablespoon at a time if sauce appears too thick. Serve immediately topped with fresh basil and additional Parmesan.