Preheat your oven to 375°F (190°C). Carefully cut the tops off the peppers and remove the seeds and membranes, creating a hollow cavity. Place the peppers cut-side up in a baking dish and drizzle lightly with a teaspoon of olive oil, then roast for 10 minutes to soften and char slightly for flavor.
While the peppers are roasting, heat a tablespoon of olive oil in a skillet over medium heat. Add the minced garlic and sauté for about 30 seconds until fragrant and slightly golden. Then stir in the cooked quinoa and smoked paprika, cooking for 2-3 minutes until well combined and heated through.
Fold in the toasted walnuts into the quinoa mixture, stirring gently to distribute evenly. Season with salt and pepper to taste. Remove from heat once everything is combined and aromatic.
Remove the peppers from the oven and carefully fill each hollow with the walnut-quinoa mixture, pressing gently to pack the filling inside. Return the stuffed peppers to the oven and bake for an additional 20 minutes, until the peppers are tender and the filling is heated through.
Switch the oven to broil, and broil the peppers for 2-3 minutes, watching closely until the tops are slightly browned and crispy. The smoky aroma and caramelized edges add the final depth of flavor.
Remove the peppers from the oven, let them rest for a couple of minutes, then transfer to a serving plate. Serve hot, garnished with additional herbs if desired, and enjoy their colorful, textured presentation.
