01 - Bring a large pot of salted water to a rolling boil. Add pasta and cook according to package directions until al dente. Reserve 1/2 cup of the starchy pasta water before draining thoroughly.
02 - While pasta cooks, heat olive oil in a large skillet over medium heat. Add chopped onion and sauté for 3-4 minutes until translucent and softened.
03 - Stir in minced garlic and cook for 1 minute until fragrant, being careful not to brown or burn it.
04 - Add tomato paste to the skillet and cook for 1 minute, stirring constantly to develop its flavor and caramelize slightly.
05 - Pour in crushed tomatoes, sugar, dried oregano, and red pepper flakes if using. Season generously with salt and pepper. Simmer uncovered over medium-low heat for 8-10 minutes, stirring occasionally until sauce thickens slightly.
06 - Reduce heat to low. Stir in heavy cream and grated Parmesan cheese. Cook for 2 minutes, allowing the cheese to melt and the sauce to become velvety and creamy.
07 - Transfer drained pasta into the sauce, tossing vigorously to coat. Add reserved pasta water a tablespoon at a time if needed to achieve silky consistency. Serve immediately topped with torn fresh basil leaves and additional grated Parmesan.