Place the chicken breasts, buttermilk and pickle juice in a large bowl or resealable bag. Marinate at least 30 minutes in the fridge.

In a large bowl, add flour, salt, pepper, paprika, garlic powder, cayenne if using, and powdered sugar. Stir to combine.

In another bowl, add egg and beat well.

Remove chicken from the marinade and dredge in the egg, then flour mixture. Make sure both sides are coated well.

Air fry at 400 degrees Fahrenheit for 15 minutes.

Flip the chicken carefully with tongs or a fork. Cook an additional 4-7 minutes until crispy. Remove from air fryer when chicken has reached an internal temperature of at least 165 degrees.

For the sauce: In a bowl, add mayonnaise, honey, bbq sauce, and mustard and mix well. In a separate small bowl, combine cornstarch and cold water. Stir mixture into the sauce to thicken.

Butter the buns and toast until golden brown. Assemble sandwiches. Add any additional toppings such as lettuce, tomato, cheese, etc. if desired.