Begin by making the blue cheese sauce: Process all the ingredients in the food processor until they're all combined.
Next, make the Buffalo Sauce:
In a small saucepan, melt the butter, on low heat. Then, stir in the rest of the ingredients. Remove from the heat. Then, reheat it on low heat right before you're ready to dip the chicken.
Next, prepare the chicken: Cut each breast in half horizontally, and then flatten each of the four pieces with a meat pounder.
In a cast iron skillet, heat about one inch of oil until it reaches 350 degrees.
As the oil heats, prepare your dredging station. Fill one bowl with the buttermilk. Divide the flour and spices between the other two bowls.
Dip each piece of chicken into the first bowl of flour, then in the buttermilk, and then back into the flour. When the oil reaches 350 degrees, fry the chicken two pieces at a time until they are golden brown on each side. They will cook about seven minutes. Do not add the second batch of chicken until the oil reheats to exactly 350 degrees. Drain all the chicken on a wire rack.
To assemble the sandwiches, dip the chicken into the warmed up Buffalo sauce. Place it on the buns along with the blue cheese sauce. Add tomato and onion if you like.