Preheat the oven to 375°F. Cut the tops off each bell pepper and remove the seeds and membranes. Use a small knife to carve simple jack-o’-lantern faces into the sides of the peppers.

Place the carved peppers in a baking dish. In a large skillet over medium heat, cook the ground beef with the diced onion until the beef is browned and the onion is soft. Drain any excess fat.

Add the minced garlic to the skillet and cook for one minute. Stir in the cooked rice, tomato sauce, chili powder, salt, and black pepper. Simmer for 3 to 4 minutes until the mixture is heated through.

Spoon the beef and rice mixture evenly into each carved pepper. Sprinkle the shredded cheddar cheese over the top of each pepper.

Bake uncovered for 25 to 30 minutes until the peppers are tender and the cheese is melted and lightly browned. Let them rest for 5 minutes before serving.