Preheat your oven to 350°F (175°C).
In a large skillet over medium heat, cook the ground beef, onion, and garlic until the beef is browned and the onion is translucent. Drain excess fat if necessary.
Stir in the tomato sauce, diced tomatoes, Italian seasoning, salt, and pepper. Bring to a simmer.
Add the uncooked elbow macaroni and beef broth to the skillet. Stir well to combine.
Cover the skillet and let it simmer for about 10 minutes, stirring occasionally, until the macaroni is tender and most of the liquid is absorbed.
Transfer the mixture to a greased 9x13-inch baking dish.
Sprinkle the shredded cheddar cheese and grated Parmesan cheese evenly over the top.
Bake in the preheated oven for 20-25 minutes, or until the cheese is bubbly and golden.
Remove from the oven and let it cool for a few minutes before serving. Garnish with chopped parsley if desired.