Bring a large pot of salted water to a boil over high heat. Add the penne pasta and cook according to package instructions until al dente, typically about 10-12 minutes. Drain the pasta but reserve 1 cup of pasta water in case you need it later for the sauce.

In a large skillet, heat 2 tablespoons of olive oil over medium heat. Add the chopped onion and minced garlic, stirring frequently for about 5 minutes until fragrant and the onion is translucent.

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

Lower the heat, pour in the heavy cream, and gently stir to combine. Gradually add the reserved pasta water to reach the desired sauce consistency, about 3-4 minutes.

Mix in the grated Parmesan cheese, stirring until it melts and becomes creamy, about 2-3 minutes. Add the cooked penne pasta, tossing gently to coat.

Remove from heat and transfer to serving bowls. Top with additional Parmesan and parsley if desired. Serve hot.