Preheat oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish.
Slice each bell pepper in half lengthwise and remove the seeds and membranes.
Arrange peppers cut-side down in the baking dish and bake for 10 minutes.
Meanwhile, heat olive oil in a large skillet over medium heat.
Add minced garlic and cook for about 1 minute until fragrant.
Add the lean ground beef, cumin, oregano, salt, and chili powder. Cook for 6–8 minutes, breaking apart the meat until fully browned.
Stir in the cooked rice, corn, diced tomato, and chopped cilantro until combined.
Remove the peppers from the oven and carefully turn them cut-side up.
Evenly fill each pepper with the beef mixture.
Sprinkle shredded cheese over each pepper.
Bake uncovered for 15 minutes until the cheese is melted and bubbly.
Garnish with chopped cilantro and serve with sour cream or Greek yogurt.
These Healthy Stuffed Peppers with Ground Beef are best enjoyed fresh but also make an excellent meal-prep option.