In a medium saucepan, combine quinoa and vegetable broth. Bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes or until the liquid is absorbed. Remove from heat and fluff with a fork.
In a skillet over medium heat, add a drizzle of olive oil. Add the diced onion and garlic, sautéing until softened, about 3-4 minutes.
In a large bowl, combine the cooked quinoa, black beans, corn, sautéed onion and garlic, diced tomatoes, cumin, chili powder, smoked paprika, salt, and pepper. Mix well until all ingredients are evenly distributed.
Cut the tops off the bell peppers and remove the seeds. If necessary, trim the bottom to ensure they stand upright.
Generously fill each pepper with the quinoa mixture, packing it in tightly.
Place the stuffed peppers upright in a baking dish. Cover with foil and bake in the preheated oven for 25 minutes. After 25 minutes, remove the foil, sprinkle the tops with shredded cheese, and bake for an additional 10 minutes, or until the cheese is melted and bubbly.
Remove from the oven, let cool for a few minutes, then garnish with fresh cilantro and serve with lime wedges on the side.
Notes
Feel free to customize the toppings with avocado or sour cream.