In a large pot of boiling salted water, cook the rigatoni according to package instructions until al dente. Drain and set aside, reserving a cup of pasta water.
In a large skillet, heat olive oil over medium heat. Add the Italian sausage, breaking it apart with a wooden spoon. Cook until browned and cooked through, about 5-7 minutes.
Stir in the diced onion and cook for 3-4 minutes until softened. Add the minced garlic and cook for an additional minute until fragrant.
Add the chopped sun-dried tomatoes and stir to combine with the sausage mixture. Cook for 2 minutes to release the flavors.
Pour in the chicken or vegetable broth and bring to a simmer. Allow it to reduce for about 5 minutes. Stir in the heavy cream and dried Italian herbs, then let it simmer for another 3-4 minutes until the sauce thickens slightly.
Add the drained rigatoni to the skillet. Toss to coat the pasta in the sauce. If the sauce is too thick, add a little reserved pasta water to reach the desired consistency.
Stir in the grated Parmesan cheese and season with salt and pepper to taste. Mix well until everything is combined and creamy.
Plate the rigatoni and sprinkle extra Parmesan cheese on top. Garnish with fresh basil leaves for a burst of color and flavor.