In a medium pot, bring the vegetable broth to a boil. Add the orzo pasta and cook according to package instructions until al dente, approximately 8-10 minutes. Drain and set aside.
While the orzo is cooking, prepare the bell peppers by cutting the tops off and removing the seeds. Brush the outside with olive oil and place them upright in a baking dish.
In a large mixing bowl, combine cooked orzo, cherry tomatoes, chopped spinach, feta cheese, Kalamata olives, lemon juice, dried oregano, garlic powder, salt, and pepper. Mix well until all the ingredients are evenly distributed.
Carefully spoon the orzo mixture into each bell pepper, packing it down gently to ensure they are well filled.
Cover the baking dish with aluminum foil and bake for 25 minutes. Then remove the foil and bake for an additional 10-15 minutes, or until the peppers are tender and the tops are slightly golden.
Once done, remove from the oven and let cool for a few minutes before serving. Garnish with fresh parsley.