Creating the Gordon Ramsay Chicken Sandwich is simple if you follow these easy steps:

1. Marinate the Chicken: In a bowl, combine the buttermilk, garlic powder, paprika, cayenne pepper, salt, and black pepper. Add the chicken breasts to the marinade, ensuring they are well-coated. Cover and refrigerate for at least 30 minutes (or overnight for best results).

2. Prepare the Coating: In a separate bowl, place the all-purpose flour and season it with salt and pepper.

3. Heat the Oil: In a large skillet, pour enough vegetable oil to cover the bottom of the pan. Heat over medium-high heat until shimmering.

4. Coat the Chicken: Remove the chicken breasts from the marinade, allowing excess liquid to drip off. Dredge each piece in the seasoned flour, pressing gently to ensure an even coating.

5. Fry the Chicken: Carefully place the coated chicken breasts in the hot oil. Fry for about 5-7 minutes on each side or until golden brown and cooked through. An internal temperature of 165°F (75°C) is recommended.

6. Drain the Chicken: Once cooked, transfer the chicken to a paper towel-lined plate to drain excess oil.

7. Prepare the Sauce: In a small bowl, mix the mayonnaise and Dijon mustard until well combined. Adjust seasoning as needed.

8. Toast the Bread: Lightly toast the slices of bread in the same skillet until golden brown.

9. Assemble the Sandwich: Spread the sauce on one side of each slice of bread. Place a piece of fried chicken on the sauce-covered side, followed by shredded lettuce and a slice of tomato. Top with the other slice of bread.

10. Garnish and Serve: Optionally, sprinkle fresh herbs on top for added flavor. Slice the sandwich in half for easy eating.