Bring a large pot of salted water to a boil. Add the rigatoni and cook according to package instructions until al dente. Drain and set aside.

Reserve about 1/2 cup of pasta water before draining.

In a skillet over medium heat, add the ground beef, diced onion, and minced garlic. Cook until the beef is browned and the onions are translucent, about 5-7 minutes.

Drain excess fat if necessary.

To the skillet with beef, add the beef broth, heavy cream, Italian seasoning, salt, and pepper. Stir to combine and bring to a simmer.

Allow the sauce to simmer for about 5 minutes, stirring occasionally.

Stir in the grated Parmesan cheese until melted and smooth.

Add the cooked rigatoni to the sauce and toss to coat. If the sauce is too thick, add reserved pasta water a little at a time until desired consistency is reached.

Serve hot, garnished with chopped parsley.