Preheat the Oven: Preheat your oven to 375°F (190°C).
Prepare the Peppers: Cut the tops off the bell peppers and remove the seeds. Place them upright in a baking dish.
Cook the Turkey: In a skillet, heat a little oil over medium heat. Add the chopped onion and garlic, cooking until softened. Add the ground turkey, cooking until browned and cooked through.
Mix the Filling: In a large bowl, combine the cooked turkey mixture, rice, diced tomatoes, Italian seasoning, salt, and pepper. Mix well to combine.
Stuff the Peppers: Fill each bell pepper with the turkey mixture, packing it down gently. If desired, top with shredded cheese.
Bake: Cover the baking dish with aluminum foil and bake for 25 minutes. Then, remove the foil and bake for an additional 10-15 minutes, or until the peppers are tender and the cheese is melted and bubbly.
Garnish and Serve: Remove from the oven, garnish with fresh herbs if desired, and serve hot.