Preheat your oven to 375°F (190°C).

If using uncooked rice, prepare it according to package instructions.

Dice the onion and mince the garlic, setting aside for easy access.

Cut tops off the bell peppers and remove seeds. Chop the tops to include in the filling if desired.

In a large skillet, brown the ground beef over medium heat until thoroughly cooked, about 5-7 minutes. Drain any excess fat.

Add the diced onion and minced garlic to the skillet, sauté until the onion is translucent, about 3 minutes.

Stir in the cooked rice, diced tomatoes (with liquid), and tomato sauce. Mix in the chopped bell pepper tops if using. Season with salt, pepper, and Italian seasoning, stirring everything together well.

Stuff the beef and rice mixture into each hollowed-out bell pepper, packing it gently but firmly.

Place the stuffed peppers upright in a large baking dish. If needed, gently press down to balance them.

Sprinkle shredded cheese on top of the stuffed peppers.

Cover the dish with aluminum foil and bake for 30-35 minutes. Remove the foil and bake for an additional 10-15 minutes until the peppers are tender and the cheese is bubbling.