1. In a large pot or Dutch oven, heat the olive oil over medium heat. Add the Italian sausage and cook, breaking it into crumbles with a wooden spoon, until it’s browned and fully cooked, about 5-7 minutes. Remove the sausage from the pot and set it aside, leaving the drippings behind.

2. Reduce the heat to low and add the reserved sun-dried tomato oil to the pot. Sauté the diced onion and minced garlic for about 3 minutes, stirring frequently, until they’re fragrant and softened.

3. Stir in the tomato paste and cook for 3 minutes, allowing it to caramelize and deepen in flavor. Then, add the chopped sun-dried tomatoes and stir to combine.

4. Pour in the chicken broth and marinara sauce. Add the rigatoni, making sure the pasta is fully submerged. If needed, add a little more chicken broth. Bring the mixture to a light boil, then reduce the heat to a simmer.

5. Cover and cook the pasta for approximately 15 minutes, stirring occasionally to prevent sticking, until the rigatoni is al dente and most of the liquid has been absorbed.

6. Stir in the heavy cream and fresh spinach. Cook for about 3 minutes, until the spinach wilts and the sauce becomes beautifully creamy. Season with Italian seasoning, red pepper flakes, salt, and pepper.

7. Turn off the heat and slowly stir in the Parmesan cheese until it’s completely melted. Add the cooked sausage back in and mix well. Adjust the seasoning if needed.

8. Serve hot, topping each portion with extra Parmesan cheese.