Begin by boiling water in a large pot. Once boiling, add the penne pasta and cook according to package instructions until al dente. Drain and set aside.
In the same pot or Dutch oven, heat the olive oil over medium heat. Add the diced onion and cook for about 3-4 minutes until softened.
Add the minced garlic to the pot and cook for an additional 1 minute until fragrant.
Add the ground beef to the pot, breaking it up with a wooden spoon. Cook until browned, stirring frequently (about 5-7 minutes).
Once the beef is cooked through, drain any excess fat, if necessary.
Pour in the beef broth and stir in the heavy cream, Italian seasoning, salt, and pepper. Bring the mixture to a gentle simmer.
Once simmering, stir in the cooked pasta and grated Parmesan cheese. Mix until everything is well combined and heated through.
Taste and adjust seasoning if necessary. Remove from heat and let sit for a couple of minutes to thicken slightly.
Serve the creamy pasta in bowls, garnished with chopped fresh parsley.