In a large pot, bring salted water to a boil and cook the penne pasta according to the package instructions until al dente. Reserve 1 cup of pasta water, then drain the rest and set aside.
While the pasta is cooking, heat olive oil in a skillet over medium heat. Add the Italian sausage and cook until browned and cooked through, breaking it into crumbles as it cooks (about 5-7 minutes).
Once the sausage is cooked, add the minced garlic to the skillet and sauté for 1-2 minutes until fragrant.
Pour in the heavy cream and chicken broth, stirring to combine. Add the Italian seasoning and bring the mixture to a simmer; cook for about 3-5 minutes to thicken slightly.
Stir in the grated Parmesan cheese, and season with salt and pepper to taste. If the sauce is too thick, add some reserved pasta water until desired consistency is reached.
Add the drained penne pasta to the skillet, tossing to coat the pasta in the creamy sauce. Cook for an additional 2 minutes to heat through.
Serve immediately, garnished with fresh parsley and additional Parmesan cheese if desired.