Prep the peppers. Heat your oven to 375°F (190°C).
Slice the tops off the bell peppers and remove the seeds and membranes. If needed, shave a thin layer off the bottoms so they stand upright. Place them in a baking dish, cut side up.
Soften the peppers (optional but recommended). Add a splash of water to the baking dish, cover with foil, and bake the empty peppers for 10 minutes.
This jump-starts cooking so they’re tender without overbaking the filling.
Sauté the aromatics. Warm olive oil in a large skillet over medium heat. Add onion and cook 3–4 minutes until softened. Stir in garlic and cook 30 seconds until fragrant.
Brown the meat. Add ground turkey to the skillet.
Cook, breaking it up with a spoon, until browned and no longer pink, about 5–7 minutes. Drain any excess fat if needed.
Season. Sprinkle in taco seasoning, salt, and pepper. Stir to coat the meat evenly and cook 1 minute to bloom the spices.
Build the filling. Add cooked brown rice, black beans, corn, diced tomatoes, and tomato sauce (or salsa).
Stir and let it simmer for 2–3 minutes. Taste and adjust seasoning. The mixture should be moist but not soupy.
Stuff the peppers. Spoon the filling into each par-baked pepper, packing it down gently and mounding a little on top.
Sprinkle with half the cheese.
Bake. Cover the dish with foil and bake 20 minutes. Uncover, add the remaining cheese, and bake another 8–10 minutes until the cheese is melted and peppers are tender.
Finish and serve. Let the peppers rest 5 minutes. Garnish with cilantro and your favorite toppings.
Serve with lime wedges for a bright finish.