Marinate Chicken: In a bowl, mix together buttermilk, salt, and cayenne. Submerge your chicken breasts in this mixture and refrigerate for at least 1 hour, up to 24 hours for deeper flavor and moisture.

Make Ranch Slaw: In a large bowl, whisk together mayonnaise, sour cream, lemon juice, apple cider vinegar, parsley, dill, salt, and pepper until smooth. Fold in the shredded cabbage and carrots, and refrigerate to allow the flavors to meld.

Prepare Dredge: In a separate bowl, combine all-purpose flour, cornstarch, paprika, garlic powder, onion powder, salt, and pepper. Remove marinated chicken from the fridge, letting excess buttermilk drip off, and dredge in the flour mixture until well coated.

Fry Chicken: Heat oil in a deep skillet to 350°F (175°C). Fry the chicken pieces for about 6-8 minutes or until they are golden brown and have reached an internal temperature of 165°F. Place them on a wire rack to keep crisp.

Sauce Chicken: Toss the fried chicken in your favorite buffalo sauce, ensuring each piece is generously coated. Adjust the amount based on how spicy you want your sandwich to be.

Assemble Sandwich: Toast brioche buns lightly. Place a piece of buffalo chicken on each bun, generously load it up with ranch slaw, and close the sandwich. Serve while hot!