1. Prepare bleu cheese spread: Mix together crumbled bleu cheese and mayonnaise. Stir together until well blended and chill.
2. Preheat oven to 350°F. Spray baking sheet with non-stick cooking spray. Wash and pat dry chicken breasts, set aside. Combine flour, salt, pepper and paprika. Coat chicken well on both sides and place on baking sheet. Bake 30 minutes, turn over and bake 30 minutes more until golden and juices run clear.
3. While chicken is baking, melt 2 sticks butter in large saucepan. Add both bottles of hot sauce and simmer on VERY low heat until chicken is done. When chicken is done, remove chicken breasts and place gently in pan with hot sauce. Coat well and continue to simmer while you prepare the sub buns. Spread each sub bun, both sides with butter and broil until golden.
TO SERVE: Place chicken breasts on one side of the sub bun, on the other side, place lettuce leaf and spread generously with the bleu cheese spread.