Preheat the oven to 375°F.

In a large skillet over medium heat, cook the ground beef or turkey until browned. Drain excess fat if necessary.

Stir in the cooked rice, black beans, corn, salsa, chili powder, cumin, salt, and pepper. Cook for about 5 minutes until heated through.

While the mixture is cooking, slice the tops off the bell peppers and remove the seeds and membranes.

Stuff each bell pepper with the meat and rice mixture, packing it down gently. Place the stuffed peppers upright in a baking dish.

Cover the baking dish with aluminum foil and bake in the preheated oven for 25 minutes.

Remove the foil, sprinkle the shredded cheese on top of each pepper, and bake for an additional 10-15 minutes, or until the cheese is melted and bubbly.

Let the peppers cool for a few minutes before serving. Garnish with fresh cilantro if desired.