Bring a large pot of salted water to a boil. Cook the pasta according to package directions until al dente. Reserve ½ cup of the pasta water, then drain.
12 ounces penne pasta
While the pasta cooks, heat a large skillet over medium-high heat. Add the sausage and cook, breaking it into small pieces as it browns, until cooked through, about 7–9 minutes.
1 pound sweet Italian sausage
Reduce the heat to medium and add the garlic. Cook for 30–60 seconds, stirring frequently, until fragrant.
3 cloves garlic
Stir in the marinara sauce, Italian seasoning and black pepper. Bring the sauce to a gentle simmer and cook for 5 minutes, stirring occasionally.
24 ounces marinara sauce , 1/2 teaspoon Italian seasoning, 1/4 teaspoon black pepper
Reduce the heat to low and stir in the heavy cream. Cook for 3-5 minutes, stirring occasionally, until heated through. Do not let the sauce boil.
1 cup heavy cream
Gradually stir in the Parmesan cheese until melted and incorporated into the sauce.
1/2 cup finely grated Parmesan cheese
Add the cooked pasta and toss until evenly coated. If the sauce is too thick, add the reserved pasta water 1 tablespoon at a time until the sauce reaches the desired consistency.
Taste and season with salt if needed. Serve topped with additional Parmesan cheese and fresh parsley, if desired.
2 tablespoons chopped fresh parsley