Dip chicken pieces in chilled water with 2 tbsp vinegar and 2 tbsp apple cider vinegar for 2 hours then remove and wash with fresh chilled water. In a bowl mix together self-raising flour and corn flour.
In a bowl mix together garlic powder, mustard powder, paprika, cinnamon powder, lemon juice, oil and salt, marinate chicken with this mixture for at least 4-6 hours.
Now dip each marinated piece of chicken in beaten egg, then in self-raising and corn flour mixture, repeat this mixture thrice, coating well in egg and flour mixture for 3 times, then deep fry.