Begin by bringing a large pot of salted water to a vigorous boil. Add the rigatoni and cook according to the package instructions until perfectly al dente. Once cooked, drain the pasta, but be sure to reserve about 1 cup of the boiling water for later use.
In a large skillet, heat the olive oil over medium heat. Introduce the Italian sausage to the pan, using a wooden spoon to break it apart. Sauté for approximately 5-7 minutes, or until the sausage is browned and no longer pink.
To the skillet, add the chopped onion and minced garlic. Stirring frequently, cook for about 3-4 minutes until the onion becomes soft and translucent, releasing its aroma.
Gradually stir in the fresh baby spinach. Continue to sauté for about 2 minutes, or until the spinach is wilted and vibrant.
Lower the heat and pour in the heavy cream, followed by the grated Parmesan cheese and Italian seasoning. Mix thoroughly until the cheese is melted and the sauce is creamy. If the sauce appears too thick, gently incorporate a bit of the reserved pasta cooking water until you reach a smooth, desired consistency. Season generously with salt, pepper, and if you enjoy some heat, sprinkle in the red pepper flakes.
Add the drained rigatoni to the skillet, tossing gently to ensure every piece of pasta is generously coated with the creamy sauce. If necessary, mix in more of the reserved pasta water until the sauce clings beautifully to the rigatoni.
Once everything is well combined, remove the skillet from the heat and let it cool slightly for a minute. Plate the creamy sausage rigatoni, and take a moment to garnish with fresh basil leaves for a pop of color.
Notes
Serve in shallow bowls, topped with extra Parmesan and fresh basil for an elegant touch.