Begin by preheating your oven to 375°F (190°C). Slice the tops off the bell peppers and remove the seeds and membranes. Brush the outsides with olive oil and set aside.
In a saucepan, combine the quinoa and vegetable broth. Bring to a boil, then reduce heat, cover, and simmer for 15-20 minutes, or until the liquid is absorbed. Fluff with a fork.
While the quinoa cooks, heat a splash of olive oil in a skillet over medium heat. Add the onion and garlic, sautéing until fragrant. Toss in the zucchini and carrot, cooking until slightly soft. Stir in the corn, black beans, cumin, paprika, salt, and pepper. Cook for another 5 minutes.
Mix the sautéed vegetables with the cooked quinoa. Adjust the seasoning to your taste.
Fill each bell pepper with the quinoa mixture and top with shredded cheese.
Arrange the peppers in a baking dish and cover with foil. Bake for about 30 minutes. Uncover and bake for an additional 10 minutes, or until the cheese is bubbly and golden.
Let the peppers cool slightly, then sprinkle with fresh cilantro before serving.