Heat olive oil in a large pot over medium-high heat.
Add ground beef to the pot and cook until browned, breaking it up with a spoon, about 5-7 minutes.
Add diced onion and cook until softened, about 3 minutes.
Stir in minced garlic, dried Italian seasoning, salt, and black pepper; cook for 1 minute until fragrant.
Pour in the diced tomatoes with their juice and beef broth. Stir to combine.
Add uncooked penne pasta to the pot and stir to submerge the pasta in the liquid.
Bring the mixture to a boil, then reduce heat to medium-low. Cover and simmer for 15 minutes, stirring occasionally to prevent sticking.
Remove the lid and cook uncovered for an additional 5 minutes, stirring occasionally, until the pasta is tender and the sauce has thickened.
Stir in grated Parmesan cheese until melted and combined.
Remove from heat and sprinkle chopped fresh parsley on top before serving.