Preheat oven to 350 degrees and spray a 9"x13" casserole dish with non-stick spray
In a large skillet (over medium-high heat) brown ground beef until nearly done. Add the diced peppers, onions, and garlic. Continue cooking until the ground beef is done and the vegetables are soft. Drain excess grease, if any.
Place beef mixture in prepared casserole dish. Add in the tomatoes, Italian seasoning, salt, pepper, tomato paste, beef broth, and uncooked rice. Stir well to make sure everything is incorporated.
Cover tightly with aluminum foil and place in oven. Bake for 1 hour, stir the mixture halfway through cooking time. This ensures the all the rice will get cooked evenly. Casserole is done when the rice is completely cooked and tender.
Remove from oven and take the foil off. Top casserole with cheese and pop back into the oven for about 5 minutes, or until the cheese is completely melted.
Some casseroles need to be made using a skillet and then baked in a casserole dish. That's how I made this meal the first time, which is this recipe. However, if you have a deep oven-safe pan with high sides, you can make this casserole in one pan from start to finish.