01 - Preheat oven to 375°F. Lightly grease a baking dish with olive oil or cooking spray.
02 - Slice the tops off the bell peppers and remove all seeds and membranes. Place the peppers upright in the prepared baking dish.
03 - In a large skillet, heat olive oil over medium heat. Sauté the onion for 2–3 minutes until softened. Add garlic and cook for 30 seconds until fragrant.
04 - Add ground chicken to the skillet. Cook, breaking it apart with a spoon, until no longer pink, about 5–7 minutes.
05 - Stir in the diced tomato, chopped spinach, parsley, dill, oregano, cumin, paprika, salt, and pepper. Cook for 2–3 minutes until the spinach wilts. Fold in cooked rice or quinoa if using, then remove from heat.
06 - Let the mixture cool slightly, then gently fold in the crumbled feta cheese.
07 - Spoon the chicken mixture into each bell pepper, packing gently to fill completely.
08 - Pour the chicken broth into the bottom of the baking dish to keep the peppers moist during baking. Cover tightly with aluminum foil and bake for 30 minutes.
09 - Remove the foil and continue baking for an additional 10 minutes until the peppers are tender and the tops are lightly golden.
10 - Garnish with additional fresh herbs and crumbled feta before serving, if desired.