Put all the dry brine ingredients in a large dish. Add the chicken, toss to coat well, then cover and chill for 12-24 hrs.
Put all the spiced flour ingredients in another dish or a large bowl, add a good grind of black pepper and combine well.
Put the buttermilk and egg in another bowl and lightly whisk until well combined.
Start to coat the chicken. Using one hand, dip the pieces in the buttermilk, making sure they are completely coated.
Using your other hand, roll the chicken in the spiced flour until covered all over.
Place the chicken on a wire rack with a baking tray underneath. Now you’re ready to start frying.
Fill a deep cast-iron frying pan or heavy- based medium saucepan half full with oil and heat until the temperature reaches 170C on a cooking thermometer. Put a wire rack on a second tray, ready to drain the fried chicken.
Heat oven to 160C/140C fan/gas 3. Place 3-4 pieces of chicken into the hot oil. Don’t overcrowd the pan. Cook for 10-12 mins. Poke your thermometer into the meat next to the bone – it will be cooked when it reaches 73C.
The oil temperature will drop when you add the chicken – adjust the heat to keep it steady at 140C during the cooking process. Once cooked, transfer to the clean wire rack and keep warm in the oven. Bring the oil back to 170C before cooking the next batch. Serve with your choice of sides.