First, make the spice mix by combining all the ingredients in a small bowl, then set aside. For the brine, whisk the buttermilk with the pickle juice, 1 tsp of salt and a third the spice mix in a plastic container or bowl until fully mixed. Cut each chicken breasts into two, about two-thirds up from the thinner end, so you have a thinner piece and a plump piece of chicken from each. One at a time, put the chicken pieces between two sheets of baking parchment and flatten out using a rolling pin until about until 2cm thick. Lower the chicken into the buttermilk mixture, then cover and chill for at least 4 hrs. Will keep covered and chilled for up to 24 hrs.

To make the coating, mix the plain flour and cornflour with the rest of the spice mix and 1 tsp of salt in a shallow dish. Make the sauce by mixing the mayonnaise with the hot sauce to taste, then set aside.

Fill a saucepan or deep-fat fryer with oil to a depth of 5cm, then heat until it reaches 175C, or until a small piece of bread dropped in quickly turns golden. When the oil is up to temperature, use tongs to lift a piece of chicken out of the buttermilk marinade, then dredge it in the seasoned flour until well coated. Carefully, still using the tongs, lower it into the oil, then repeat with a second piece of chicken. Fry for 5 mins, until deeply golden and crisp on both sides. Lift the chicken out and drain on a tray lined with kitchen paper, then cover with a slice of cheese and put on a rack in a low oven to keep warm while you fry the rest of the chicken burgers.

Split the buns, spread the cut sides with a little mayonnaise and toast in a large frying pan until browned and crisp. Once all the chicken is cooked, build the burgers. Spread the bottom halves of the buns with some of the sauce, add the chicken, lay over the slices of gherkin, spread the cut sides of the remaining bun halves with more sauce, then close the burgers. Serve straightaway with napkins.