01 - Preheat the oven to 375°F. Prepare a baking dish for the peppers.
02 - Slice the tops off each bell pepper and remove the seeds and membranes. Carefully carve jack-o’-lantern faces into the sides using a small paring knife.
03 - Set the prepared peppers upright in the baking dish.
04 - Heat olive oil in a large skillet over medium heat. Add diced onion and cook until softened, about 5 minutes. Add minced garlic and sauté for 1 minute.
05 - Stir in cooked brown rice, black beans, corn, drained diced tomatoes, ground cumin, smoked paprika, chili powder, salt, and black pepper. Cook for 3–4 minutes, stirring occasionally.
06 - Remove the skillet from the heat and mix in shredded cheddar cheese and chopped cilantro, if using.
07 - Evenly fill each bell pepper with the prepared black bean mixture, pressing gently to pack. Top with extra cheese if desired.
08 - Replace the tops on the peppers. Add a splash of water to the bottom of the baking dish, cover with foil, and bake for 30 minutes.
09 - Remove the foil and bake for an additional 10 minutes, until peppers are tender and cheese is melted.
10 - Remove from the oven and serve warm.