In a skillet on medium heat, add 1/2 cup oil. You can either use the oil used from browning the wings and onions or fresh oil. I prefer the latter.
Once the oil is hot, sprinkle in the remaining flour from coating the wings. Cook until nice and brown and stir continuously.
Slowly pour in the chicken broth and continue to stir until completely mixed.
Taste the gravy to see if more seasoning is needed. Once the gravy is to your liking, pour it over the turkey wings in the slow cooker.
Place the lid on the slow cooker and set for 3 hours on high or 6 hours on low.
Serve with rice or mashed potatoes.