01 - In a large pot, bring generously salted water to a rolling boil. Add penne or fettuccine and cook according to package instructions until al dente. Reserve 1/2 cup of the pasta cooking water before draining the pasta.
02 - While the pasta cooks, heat olive oil in a large skillet or Dutch oven over medium heat. Add the finely chopped onion and sauté for 3 to 4 minutes until translucent. Incorporate the minced garlic and cook for an additional minute until fragrant.
03 - Pour in the canned crushed tomatoes. Stir in the salt, black pepper, and optional sugar to balance acidity. Bring to a gentle simmer, then reduce heat and continue to cook for 10 minutes, stirring occasionally to prevent sticking.
04 - Reduce heat to low. Stir in the heavy cream and grated Parmesan cheese. Allow to gently simmer for 2 to 3 minutes, or until the sauce achieves a creamy consistency and slightly thickens.
05 - Add the drained cooked pasta directly to the skillet with the sauce. Toss thoroughly to ensure all pasta is evenly coated. If the sauce appears too thick, gradually add small amounts of the reserved pasta water until the desired consistency is achieved.
06 - Remove the skillet from the heat. Gently fold in the fresh basil leaves until just wilted and fragrant.
07 - Dish out the creamy tomato basil pasta immediately. Garnish each serving with additional grated Parmesan cheese and a few fresh basil leaves.