Combine the flour, salt, pepper, cayenne, onion, and garlic powder. Put 2 cups (240 g) of all-purpose flour into a large sealable plastic bag. Add 1 teaspoon (2 g) of onion powder, 1 teaspoon (2 g) of garlic powder, the remaining 1 teaspoon (6 g) of kosher salt, the remaining 1 teaspoon (2 g) of freshly ground black pepper, and the remaining 1/2 teaspoon (1 g) of cayenne pepper. Seal and shake the bag
If you prefer, mix the flour and seasoning in a large shallow dish instead of a bag.
Set a rack on a sheet and remove the chicken from the marinade. Place a wire rack on a baking sheet and set it next to your work surface. Then uncover the chicken and lift each piece out of the buttermilk marinade
Hold each piece up for a few seconds so the excess marinade drips back into the bowl.
Place the chicken into the bag with the seasonings and shake it. Put all of the chicken pieces into the bag or work in batches if all of them won't fit. Seal the bag shut and shake it until the chicken is completely coated with the dry seasoning