Preheat your oven to 350°F (175°C). Lightly grease a baking dish with cooking spray.
Using a small sharp knife, carefully cut jack-o'-lantern faces into one side of each bell pepper. Slice off the tops and remove the seeds and membranes.
Heat olive oil in a skillet over medium heat. Sauté the onion until soft, about 3–4 minutes. Add garlic and cook for another minute.
Add ground beef to the skillet and cook until browned. Drain any excess fat.
Stir in cooked rice, tomato sauce, Italian seasoning, salt, and pepper. Simmer for 5–7 minutes until heated through.
Stuff each pepper with the beef and rice mixture. Top with shredded cheese and replace the pepper tops.
Place stuffed peppers in the prepared baking dish. Cover with foil and bake for 30 minutes.
Remove foil and bake for an additional 10 minutes until peppers are tender and cheese is melted.