Preheat the oven to 375°F (190°C).

Cut the tops off the bell peppers and remove the seeds and membranes.

In a skillet, cook the ground beef with chopped onion and minced garlic until browned.

Stir in cooked rice, diced tomatoes, Italian seasoning, salt, and black pepper. Mix well.

Stuff each bell pepper with the meat and rice mixture.

Place the stuffed peppers upright in a baking dish and sprinkle with shredded cheese.

Cover with foil and bake for 25 minutes. Remove foil and bake for an additional 5 minutes until cheese is melted.