Preheat your oven to 375°F (190°C). Gather a large oven-safe skillet or Dutch oven for cooking.

Heat olive oil over medium-high heat in the skillet. Add Italian sausage and sauté until browned and crispy (about 5-7 minutes). Remove sausage and set aside.

In the same skillet, add chopped onion and sauté for 5-6 minutes until translucent. Add minced garlic and cook for another minute.

Stir in crushed tomatoes and red pepper flakes (if using). Let simmer for about 10 minutes until slightly thickened.

Bring a large pot of salted water to a boil. Add rigatoni and cook until just under al dente. Drain, reserving 1 cup of pasta water.

Stir heavy cream and Parmesan cheese into the tomato sauce. Return the sautéed sausage to the skillet and mix.

Add cooked rigatoni to the sauce, tossing gently to coat. If sauce is too thick, add reserved pasta water gradually.

Transfer the skillet to the preheated oven and bake for 20-25 minutes until bubbling and golden.

Let rest for 5-10 minutes, then garnish with fresh basil and extra Parmesan before serving.