Heat the olive oil in a large pot or deep skillet over medium heat.
Add the diced onion and cook for 3-4 minutes until softened.
Add the minced garlic and cook for 1 minute until fragrant.
Add the ground beef to the pot and cook, breaking it apart with a spoon, until browned and cooked through, about 6-8 minutes.
Drain any excess fat from the pot.
Stir in the uncooked penne pasta, beef broth, diced tomatoes with their juice, dried Italian seasoning, salt, and black pepper.
Bring the mixture to a boil, then reduce heat to medium-low and cover the pot.
Simmer for 12-15 minutes, stirring occasionally, until the pasta is tender and most of the liquid is absorbed.
Stir in the heavy cream, mozzarella cheese, and Parmesan cheese until the cheese is melted and the sauce is creamy.
Cook for an additional 2-3 minutes, stirring frequently, until heated through.
Remove from heat and let stand for 2 minutes before serving.