Sauté the aromatics. In a large, wide pot or deep sauté pan, heat the olive oil over medium heat.
Add the onion with a pinch of salt and cook 4–5 minutes until soft and translucent. Stir in the garlic and red pepper flakes; cook 30 seconds until fragrant.
Build the base. Add crushed tomatoes, broth, oregano, and sugar if using. Stir well and season with 1 teaspoon salt and 1/2 teaspoon black pepper to start.
Add the pasta. Stir in the dry pasta, pressing it down so it’s mostly submerged.
Increase heat to bring the mixture to a lively simmer.
Simmer and stir. Cook uncovered, stirring often to prevent sticking, for 10–12 minutes or until the pasta is al dente. Adjust the heat to keep a steady simmer. If the liquid reduces too quickly, splash in more broth or water, 1/4 cup at a time.
Make it creamy. Lower the heat and pour in the cream.
Stir in the Parmesan until melted and the sauce turns glossy and slightly thick. Taste and adjust salt and pepper.
Finish with basil. Remove from heat and fold in most of the basil, reserving a little for garnish. Let the pasta rest 2–3 minutes; it will thicken as it sits.
Serve. Top with extra Parmesan, a drizzle of olive oil, and the remaining basil.
Serve hot.