Prep the peppers. Preheat your oven to 400°F (200°C).
Slice bell peppers in half lengthwise, remove seeds and membranes, and place cut side up on a baking sheet. Drizzle with olive oil and season with a pinch of salt and pepper.
Par-bake the peppers. Bake for 10–12 minutes until slightly softened. This ensures tender, not crunchy, peppers after stuffing.
Cook the meat. While peppers roast, heat a large skillet over medium-high heat.
Add ground beef (or turkey/chicken) and cook, breaking it up, until browned and cooked through. Drain excess fat if needed.
Add aromatics and seasoning. Stir in chopped onion and cook 3–4 minutes until softened. Add garlic and cook 30 seconds.
Sprinkle in taco seasoning and a splash of water, stirring to coat the meat evenly.
Build the filling. Add cooked rice, black beans, and corn. Stir in salsa and simmer 2–3 minutes to let flavors blend. Taste and adjust with salt and pepper.
Stir in 1/2 cup of the shredded cheese to make the filling a little creamy.
Stuff the peppers. Spoon the hot filling into each par-baked pepper half, mounding it slightly. Arrange them snugly on the baking sheet or in a casserole dish so they stand upright.
Add cheese on top. Sprinkle the remaining cheese generously over each stuffed pepper.
Bake to bubbly perfection. Return to the oven and bake 12–15 minutes, until the cheese is melted, golden in spots, and the peppers are tender.
Finish and serve. Let cool for a few minutes. Garnish with cilantro or green onions.
Serve with optional toppings like sour cream, avocado slices, and lime wedges for brightness.