Cook the Quinoa: In a medium saucepan, combine the rinsed quinoa and the no-salt-added vegetable broth. Bring to a boil, then immediately reduce the heat to its lowest setting. Cover and simmer for 15 minutes, or until all the broth is absorbed. Remove from the heat and let stand, covered, for 10 minutes before fluffing with a fork.
Roast the Peppers: While the quinoa cooks, preheat your oven to 400°F (200°C). Arrange the bell pepper halves, cut-side up, in a 9x13-inch baking dish. Drizzle lightly with about half of the olive oil. Roast for 15-20 minutes, until they just begin to soften. Remove from the oven and set aside.
Build the Aromatic Base: In a large skillet, heat the remaining olive oil over medium heat. Add the diced yellow onion and sauté for 5-6 minutes until softened and translucent. Add the minced garlic and dried oregano, cooking for another minute until fragrant.
Create the Filling: Add the fresh spinach to the skillet in large handfuls, stirring continuously until it wilts completely. Stir in the chopped artichoke hearts and the rinsed chickpeas, cooking for 2-3 minutes to warm through.
Combine the Filling: Remove the skillet from the heat. Add the cooked quinoa to the spinach mixture, followed by the Greek yogurt, fresh parsley, dill, lemon zest, lemon juice, and black pepper. Stir until everything is thoroughly combined into a cohesive, creamy filling.
Assemble and Bake: Carefully spoon the quinoa filling evenly into each of the pre-roasted pepper halves, mounding it slightly. Sprinkle the crumbled feta cheese over the top of each stuffed pepper. Return the dish to the oven and bake for an additional 10-15 minutes, or until the filling is heated through and the feta is lightly golden. Serve immediately.