Marinate the chicken in seasoned buttermilk for at least 30 minutes to tenderize and infuse flavor.
Prepare a seasoned flour mixture with cornstarch and spices, ensuring even distribution for consistent coating.
Coat each chicken piece thoroughly, pressing the flour mixture firmly so it adheres well.
Heat oil to the correct temperature and fry the chicken until golden and cooked through, maintaining steady heat.
Let the chicken rest on a rack to preserve crispiness.
Toast buns lightly and assemble the sandwich with sauces, vegetables, and crispy chicken just before serving.