Prep the chicken: 12-24 hours before: Add the chicken to enough buttermilk that they are submerged. Refrigerate until ready to cook. The buttermilk will help tenderize the meat.
Wash and pat dry the thighs. Season with salt and pepper.
Bread the thighs: Dredge in flour, then egg, then breadcrumbs until evenly coated.
Make the buffalo butter: Melt butter with Frank's RedHot until smooth.
Fry: Heat a shallow layer of oil in a skillet over medium heat. Fry each thigh for 3–4 minutes per side until golden brown and cooked through. Transfer to a wire rack and brush with the buffalo butter.
Toss the salad: Combine romaine, pickled carrots, and blue cheese dressing.
Assemble: Add chicken to toasted brioche buns, top with salad, and finish with extra blue cheese dressing.