Trim the excess fat off the sides of the chicken breast. Using a knife, score the chicken longways, cutting halfway through the chicken to help it cook more rapidly.
In a medium-sized mixing bowl, crack the eggs and whisk with the milk.
In a separate medium-sized mixing bowl, add the bread crumbs.
Dip each chicken breast in the egg mixture, covering it completely, then transfer to the bread crumbs and coat completely. Repeat this process one more time.
Transfer to a parchment-lined baking sheet.
Fit a Dutch oven with thermometer and pour in oil for frying. Heat over medium-high until thermometer registers 340˚F (170˚C).
Set the chicken breasts in, in batches, and fry for 2-3 minutes until golden brown.
Place fried chicken on a wire rack set over a baking sheet, to drain. Sprinkle with salt.
Prepare the spicy pepper oil in a small mixing bowl by whisking together all the spices with the sunflower oil, until all the spices have dissolved into the oil. Set aside.
Transfer the fried chicken to the brioche buns.
Whisk together the spicy oil so none of the seasoning settles to the bottom.
Drizzle 2 tablespoons over each chicken breast.
Add 3 bread and butter pickles on top of the chicken and place the top bun.