Prepare and Marinate the Chicken: Place each chicken breast between two sheets of baking parchment and gently pound it with a rolling pin or meat mallet to an even thickness of about 2cm. In a medium bowl, whisk together the buttermilk, pickle brine, 1 tsp salt, and 1/2 tsp pepper. Add the chicken breasts, ensuring they are fully submerged. Cover and refrigerate for at least 2 hours, or up to 8 hours for maximum tenderness.

Mix the Spiced Flour: In a wide, shallow dish, combine the plain flour, cornflour, smoked paprika, cayenne pepper, garlic powder, onion powder, 2 tsp salt, and 1 tsp black pepper. Whisk thoroughly to ensure all the spices are evenly distributed.

Make the Spicy Sauce: While the chicken marinates, prepare the sauce. In a small bowl, simply mix the mayonnaise, sriracha, smoked paprika, and lemon juice until smooth. Cover and pop it in the fridge until you're ready to serve. This gives the flavours time to meld together. If you're a fan of punchy sauces, my Bang Bang Chicken Thighs recipe has another sauce you might love.

Dredge the Chicken (The Double-Dip): Set up your dredging station. Take one piece of chicken from the marinade, letting the excess drip off but don't wipe it dry. Press it firmly into the flour mixture, coating all sides. Then, dip it *back* into the buttermilk marinade for a second, and then a final time back into the flour. Really press the flour on to create a thick, craggy coating. I find this double-dip is essential for that extra-crispy result. Set the coated chicken on a wire rack and repeat with the remaining pieces. Let them rest for 10-15 minutes – this helps the coating adhere properly during frying.

Heat the Oil: Pour the oil into a large, heavy-bottomed pot or Dutch oven to a depth of about 5cm. Heat the oil over a medium-high heat to 175°C (350°F). Use a cooking thermometer for accuracy; maintaining the right oil temperature is key to crispy, not greasy, chicken.

Fry the Chicken: Carefully place two pieces of chicken into the hot oil, ensuring you don't overcrowd the pan. Fry for 4-6 minutes on each side, until deep golden brown, crisp, and cooked through. The internal temperature should reach 74°C (165°F). You can find more information about cooking chicken safely on the Food Standards Agency website. Remove the cooked chicken with tongs and place it on a clean wire rack to drain. Let the oil come back to temperature before frying the next batch.

Assemble Your Sandwich: Lightly toast the brioche buns. Spread a generous amount of the spicy sauce on both the top and bottom bun. Place the hot, crispy chicken on the bottom bun, top with a few slices of dill pickle, and place the top bun on. Serve immediately while the chicken is at its crispy best.