1) Marinate the chicken pieces in a bowl with the buttermilk and place in the fridge for 12 hours. 2) Preheat the oven to 180C/375F/Gas 4. 3) Mix together all of the dry ingredients in a large bowl and season. 4) Remove the chicken from the buttermilk and shake off as much liquid as possible. 5) Toss the chicken pieces in the mixture until coated. 6) Pour the oil into a large high sided frying pan or wok and place over a medium-high heat until a piece of bread floats to the surface when dropped in. 7) Fry 3-4 pieces of chicken at a time, for 5 - 7 minutes until golden-brown. Allowing the oil to re heat before adding the next batch. 8) Drain the chicken on kitchen paper and then transfer to a roasting tin as you go. 9) Put the chicken pieces in the oven and cook for a further 10 - 15 minutes until the coating is crunchy and the chicken cooked through. 10) Rest for 5 minutes before serving.