Preheat your oven to 375°F (190°C).
Cut the tops off the bell peppers and remove the seeds and membranes.
Place them in a baking dish.
Heat a skillet over medium heat. Add the ground beef and cook until browned (about 5–7 minutes). Drain excess fat if needed.
Add the diced onion and cook for 3 minutes. Stir in the garlic and cook for another minute.
Mix in the cooked rice, half of the tomato sauce, Worcestershire sauce, salt, pepper, and Italian seasoning. Stir well.
Spoon the beef mixture into each bell pepper, filling them evenly.
Pour the remaining tomato sauce over the tops of the peppers.
Cover with foil and bake for 30 minutes.
If using cheese, uncover the peppers, sprinkle cheese on top, and bake for an additional 5–10 minutes until melted.
Let the peppers cool for a few minutes before serving.