Bring a large pot of heavily salted water to a rolling boil. Add the rigatoni and cook according to package directions, typically 8-10 minutes, until al dente. Drain well and set aside. Do not rinse.

While the pasta cooks, heat olive oil in a large skillet or Dutch oven over medium heat. Add the finely diced onion and cook, stirring occasionally, until softened and translucent, about 5-7 minutes.

Add the minced garlic and red pepper flakes (if using) and cook for another 1 minute until fragrant, being careful not to burn the garlic.

Pour in the crushed tomatoes, dried oregano, salt, and black pepper. Bring the sauce to a gentle simmer, then reduce heat to low, cover, and let it cook for 15-20 minutes, allowing the flavors to meld. Stir occasionally to prevent sticking.

Remove the sauce from heat. Stir in the heavy cream and 1/4 cup of grated Parmesan cheese until fully combined and the sauce has a uniform pink color. Taste and adjust seasoning if needed. Finally, stir in 1/4 cup of fresh chopped basil.

Preheat your oven to 375°F (190°C).

In a large mixing bowl, combine the cooked rigatoni with the pink sauce, ensuring all pasta is evenly coated.

Pour the sauced rigatoni into a 9x13 inch (or similar size) oven-safe baking dish, spreading it into an even layer.

Evenly sprinkle the shredded mozzarella cheese and the remaining 1/2 cup of grated Parmesan cheese over the top of the pasta.

Bake for 20-25 minutes, or until the cheese is melted, bubbly, and lightly golden brown. If you prefer a darker, crispier top, you can briefly broil it for 1-2 minutes, watching carefully to prevent burning.

Remove from oven and let it rest for 5-10 minutes before serving. Garnish with additional fresh basil, if desired, and extra Parmesan cheese.