Heat the oven to 350 degrees.
Place the chicken wings into a large bowl with the onion powder, cajun seasoning, paprika, poultry seasonings, garlic powder and celery salt. Mix to coat well.
Add the wings to a large baking sheet, and place the onions and peppers on top.
Cover the baking sheet with tin foil and bake for 1 hour and 15 minutes.
Remove the pan from the oven and drain off the drippings. Place the pan back into the oven.
In a skillet over medium heat, add the drippings and the flour. Stir to combine well.
Whisk in the broth a little at a time, and then add in the garlic powder and onion powder.
Saute until the gravy is thick.
Pour the gravy over the turkey legs and bake for another 30 minutes uncovered.