Cut the tops off the bell peppers and remove the seeds and membranes. Set them aside.
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 quinoa is fluffy and broth is fully absorbed.
In a large mixing bowl, combine the cooked quinoa, black beans, corn, diced tomatoes, cumin, chili powder, garlic powder, salt, and pepper. Mix well until all ingredients are evenly incorporated.
Carefully stuff each bell pepper with the quinoa mixture, packing it lightly to fit as much filling as possible.
Place the stuffed peppers upright in a baking dish. If they don’t stand well, you can trim the bottom slightly to level them.
Sprinkle the shredded cheddar cheese generously over the top of each stuffed pepper.
Cover the dish with aluminum foil and bake in the preheated oven for 25 minutes. Then, remove the foil and bake for an additional 10 minutes or until the peppers are tender and the cheese is bubbly and golden.
Remove from the oven and let cool slightly before serving.
Garnish with fresh cilantro and serve with avocado slices on the side.
Notes
Feel free to customize the spices and toppings to your liking.