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