Sprinkle the chicken all over with salt and pepper. Set aside.
Set up a dredging station with three pans or bowls. In the first, mix together the flour with ½ tsp of salt and ½ tsp black pepper. In the second pan, whisk together the buttermilk with the egg. In the third, mix together the bread crumbs, garlic powder, chili powder, and seasoned salt.
Dredge one or two pieces of chicken through the flour to completely coat, shaking off excess. Place the floured chicken in the buttermilk/egg mixture and press down to fully coat. Lift the chicken up and shake off excess buttermilk/egg. Dredge the chicken through the breadcrumb mixture until fully coated. Place on platter and repeat process until all chicken is coated.
Heat the oil in a large saucepan/skillet. When shimmering, add 3 tbsp of butter, and swirl with a wooden spoon until melted. Working in batches, add the chicken to the pan and cook until the underside of the cutlet is golden brown, about 4 to 5 minutes. Use tongs to carefully flip the cutlet over and cook for another 4 to 5 minutes, or until golden brown and cooked through with an internal temperature of 165°F. Place the cooked cutlets on a platter or plate lined with paper towels.
Meanwhile, pour the buffalo wing sauce into a medium-sized saucepan and heat over medium-low heat.
Place the chicken cutlets in a large dish and ladle the warm sauce all over. Save some of the sauce for passing tableside.
Meanwhile, butter the buns and toast until just browned.
Build the sandwich by adding about 1 tbsp (or more) of the blue cheese dressing on the bottom bun. Add two of the buffalo chicken cutlets on the dressing, and top with shredded lettuce and top bun. Serve at once with additional wing sauce and blue cheese dressing.