Bring a large pot of salted water to a rolling boil over high heat. Add the penne pasta and cook according to package instructions until al dente, about 10-12 minutes. Once cooked, drain the pasta, reserving about 1 cup of the starchy pasta water.

In a large skillet over medium heat, pour in 2 tablespoons of olive oil and allow it to heat for a minute. Add the diced yellow onion and minced garlic, sautéing until translucent and fragrant, about 5 minutes.

Add the lean ground beef to the skillet, breaking it apart with a wooden spoon. Cook until browned and no longer pink, about 7 minutes. Season with salt, pepper, and Italian seasoning.

Lower the heat to medium-low and slowly pour in the heavy cream, stirring gently. Gradually add reserved pasta water until desired creaminess, mixing in the Parmesan cheese until melted.

Add the drained penne to the skillet, tossing to coat all pasta pieces in the sauce. Let cook together for a minute to heat through.

Plate immediately, garnishing with extra Parmesan cheese or parsley. Serve hot.