Preheat oven to 375°F (190°C).
Heat olive oil in a large skillet over medium heat.
Cook ground beef and onion until browned and drain excess fat.
Add chopped bell peppers and cook for 3–4 minutes.
Stir in garlic and cook for 30 seconds.
Add uncooked rice, beef broth, diced tomatoes, and tomato sauce.
Season with Italian seasoning, salt, and black pepper.
Transfer mixture to a greased baking dish.
Cover with foil and bake for 25 minutes.
Remove foil, sprinkle cheese on top, and bake uncovered for 10 more minutes until cheese melts.
Let rest 5 minutes before serving.