Preheat the oven to 400℉ and lightly grease a baking dish. Set aside.
In a small bowl, combine salt, black pepper, Cajun seasoning, parsley, paprika, poultry seasoning, garlic powder, and onion powder.
Pat the turkey wings dry and place them in a mixing bowl.
Drizzle with oil and sprinkle the seasoning blend evenly over the wings. Use your hands to ensure the wings are well coated on all sides.
Arrange the wings in the greased baking dish in a single layer, avoiding overlap.
Scatter the chopped onions, celery, and bell peppers over the wings. Add butter and pour in 1 cup of broth.
Cover the dish with aluminum foil and bake for at least 1 hour. The cooking time may vary depending on the size of the wings.
Once cooked, transfer the pan drippings to a skillet or saucepan. Add flour and whisk to combine. Simmer until the mixture thickens. Adjust the consistency by adding more broth or water if needed.
Pour the prepared gravy over the turkey wings. Return the dish to the oven, uncovered, and bake for another 30 minutes, allowing the sauce to thicken and the wings to become extra tender.
Remove from the oven and serve warm.