In a large oven-safe skillet or pan over medium-high heat, brown the ground beef until no longer pink, breaking it apart as it cooks, about 6-8 minutes. Drain excess fat if needed.

Add the diced bell peppers, onion, and minced garlic to the pan with the beef. Cook for 4-5 minutes until vegetables begin to soften, stirring occasionally.

Stir in the uncooked rice, diced tomatoes with their juices, beef broth, Italian seasoning, salt, and black pepper. Mix everything together well.

Bring the mixture to a boil, then reduce heat to low. Cover the pan with a lid and simmer for 20-25 minutes until the rice is tender and has absorbed most of the liquid, stirring occasionally.

Preheat your broiler. Stir in 1 cup of the shredded mozzarella cheese into the casserole, then sprinkle the remaining 1 cup of cheese evenly over the top.

Place the uncovered pan under the broiler for 2-3 minutes until the cheese is melted and bubbly with golden spots. Watch carefully to prevent burning.

Remove from oven and let the casserole rest for 5 minutes before serving. Garnish with fresh parsley if desired and serve hot.