The zesty sauce was popularized in Decatur, Alabama and is commonly served on smoked chicken though I enjoy it slathered over crispy, fried chicken as in this recipe.
Fill a large cast iron pan with vegetable oil so it reaches 2-inches up the pan. Heat the oil to 350°F (180ºC).
In a medium shallow bowl add the flour. Whisk the buttermilk and egg together in another medium bowl. Season chicken with salt and pepper. One piece at a time, dip chicken in the buttermilk mixture then dredge in the flour.
Shake off any excess flour and fry in the oil, flipping once, until the chicken is golden brown on all sides, about 8 minutes. Remove the chicken and allow to drain on a paper towel-lined plate.
For the Alabama white sauce:
In a medium mixing bowl whisk together the mayonnaise, apple cider vinegar, brown sugar, horseradish, Worcestershire, red pepper flakes, black pepper, garlic powder and onion powder with 1 tablespoon of water until completely combined. Cover and refrigerate until ready to use.
For serving:
Add a piece of fried chicken to the bottom half of each sandwich bun. Top with shredded cabbage, pickles and a drizzle of the Alabama white sauce. Close the sandwich and serve immediately.