Brown the ground beef in a large skillet over medium heat. Drain any excess fat.
Add chopped onion and bell peppers to the skillet. Sauté until softened, about 5 minutes.
Stir in the garlic and cook for another minute.
Add the diced tomatoes (with their juice), cooked rice, Italian seasoning, salt, and pepper. Stir everything together.
Cover and simmer for 5–10 minutes, letting the flavors blend.
Sprinkle cheese over the top. Cover until melted.
Garnish with chopped parsley if using. Serve hot.