Cut the tops off the bell peppers and remove the seeds and membranes. Place the peppers upright in a baking dish.
In a medium saucepan, combine the quinoa and vegetable broth. Bring to a boil, then reduce heat to low, cover, and simmer for about 15-20 minutes, or until the quinoa is fluffy and the liquid is absorbed.
In a large mixing bowl, combine the cooked quinoa, black beans, corn, diced tomatoes, chopped red onion, minced garlic, cumin, chili powder, smoked paprika, salt, and black pepper. Mix until well incorporated.
Stuff each bell pepper with the quinoa mixture, pressing down gently to pack it in.
Top each stuffed pepper with shredded cheese.
Cover the baking dish with aluminum foil and bake in the preheated oven for 30 minutes.
Remove the foil and bake for an additional 10-15 minutes, or until the peppers are tender and the cheese is bubbly and golden.
Remove from the oven and let cool for a few minutes before serving.
Notes
Serve with fresh cilantro and a wedge of lime for added flavor.