Marinate the chicken. Whisk the buttermilk with the salt, smoked paprika, garlic granules, onion granules and cayenne. Add the chicken cutlets, turn to coat, cover, and leave in the fridge for at least 30 minutes. Overnight is better if you've planned ahead.

Make the dredge. In a wide bowl, combine the plain flour, cornflour, baking powder, a good pinch of salt and plenty of black pepper. Whisk it together so there are no lumps.

Heat the oil. Pour your neutral oil into a deep, heavy pan and bring it to 175-180°C. If you don't have a thermometer, drop in a small cube of bread; it should sink briefly, then rise and fizz steadily without burning.

Coat the chicken. Lift each cutlet out of the buttermilk, letting the excess drip back into the bowl, then press it firmly into the flour mixture on both sides. Shake off the loose flour and set the coated pieces on a rack while you finish the rest.

Fry. Lower two pieces at a time into the oil. Don't crowd the pan. Fry for 4-5 minutes per side, turning once, until deep golden and cooked through at the thickest point.

Drain and rest. Move the cooked chicken to a wire rack rather than kitchen paper. Rest for 5 minutes.

Toast the buns. Wipe out the pan, or use a separate one, and melt the butter over medium heat. Press the cut sides of the buns into the pan for 60-90 seconds until golden and slightly crisp at the edges.

Build. Spread mayo or fry sauce on both bun halves. Lay lettuce on the base, then the chicken, then pickles, tomato and onion. Top and press down gently before eating.