01 - Preheat oven to 375°F. Lightly grease a baking dish with olive oil.
02 - Slice the tops off the bell peppers and remove all seeds and membranes. Arrange the peppers upright in the prepared baking dish.
03 - Heat olive oil in a large skillet over medium heat. Sauté the onion for 2 to 3 minutes until softened. Add the garlic and cook for an additional 30 seconds until fragrant.
04 - Add the ground chicken to the skillet. Cook, breaking it apart with a spoon, until no longer pink, about 5 to 7 minutes.
05 - Stir in the diced tomato, chopped spinach, parsley, dill, oregano, cumin, paprika, salt, and pepper. Cook for 2 to 3 minutes until the spinach wilts. Fold in the cooked rice or quinoa if using, then remove from heat.
06 - Allow the mixture to cool slightly, then gently fold in the crumbled feta cheese.
07 - Fill each bell pepper with the chicken mixture, packing it gently to ensure even distribution.
08 - Pour the chicken broth into the bottom of the baking dish to keep the peppers moist during baking. Cover the dish 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 extra fresh herbs and crumbled feta before serving, if desired.