Place the chicken breasts between two sheets of plastic wrap and gently pound them to an even thickness for uniform cooking.
In a bowl, whisk together the buttermilk and a pinch of salt; set aside.
In another bowl, combine the flour, cornstarch, garlic powder, paprika, cayenne, black pepper, and salt to create your seasoned dredging mixture.
Dip each chicken breast into the seasoned flour, then into the buttermilk mixture, allowing excess to drip off.
Re-dip the chicken into the seasoned flour, pressing gently to adhere for a thick, crispy coating.
Heat vegetable oil in a deep skillet over medium-high heat until shimmering and bubbling gently—about 350°F (175°C).
Carefully place the coated chicken breasts into the hot oil, frying until golden brown and cooked through, about 6-8 minutes per side.
Transfer the fried chicken to a cooling rack set over paper towels to drain excess oil and maintain crispness.
Slice the pickles thinly and prepare the buns, toasting lightly if desired for extra texture and flavor.
Assemble the sandwich by placing the crispy chicken fillet on the bottom bun, layering with pickles, then topping with the top bun.
Serve immediately while the chicken is crispy and hot, enjoying the layered crunch and tender contrast in every bite.
