Cut chicken breasts in halves by placing hand on top of chicken breast, then use other hand to cut horizontally through the thick side of the chicken breast using a very sharp knife. Cut all at way through until you have 2 halves. Then, cut each halve into 3 pieces. You should have a total of 12 pieces of chicken.
To marinate the chicken, add chicken pieces to a bowl and season with garlic powder, sea salt and cayenne pepper. Make sure each piece is seasoned thoroughly. Stir in hot sauce and buttermilk. Mixture should be a pinkish color. Cover and refrigerate for at least 1 hour.
Remove chicken from refrigerator and let rest until it reaches room temperature, about 20 minutes. In a small bowl, whisk flour, corn starch, sea salt, garlic powder, onion powder and cayenne pepper together. Take each piece of chicken from buttermilk mixture and coat in flour mixture until each piece is thoroughly coated. Let chicken for 15 minutes before frying.
Heat an inch of oil in a skillet until heat reaches 365 degrees. This can be done over medium to medium-high heat. Cook each piece of chicken for 4 minutes on one side, then flip and cook for 2 minutes on other side. Do not crowd skillet with chicken. If using a 10 inch skillet, try to add no more than four pieces. If using a 12 inch skillet, try to add no more than six pieces. I use a 12 inch cast iron, and normally need to cook in 2 batches. Let chicken rest on a wire rack, while you prepare buns.
Toast buns and add piece of chicken to each, with toppings and condiments of choice. Recommend mayo, lettuce and pickle.