01 - In a mixing bowl, whisk together buttermilk, hot sauce, and Cajun seasoning. Add the chicken breasts, ensuring they are fully submerged. Cover and refrigerate for at least 30 minutes, or up to 4 hours for enhanced flavor.
02 - In a separate bowl, blend flour, corn starch, Cajun seasoning, garlic powder, paprika, salt, and black pepper until well combined.
03 - Remove marinated chicken from the bowl, allowing excess marinade to drip off. Coat each breast thoroughly in the flour mixture, pressing gently to ensure a thick, even layer.
04 - Heat vegetable oil in a deep skillet or Dutch oven to 350°F (175°C). Fry the coated chicken breasts for 6 to 8 minutes per side until golden and an internal temperature of 165°F (75°C) is reached. Transfer to paper towels to drain any excess oil.
05 - Combine mayonnaise, minced garlic, lemon juice, Dijon mustard, salt, and pepper in a small bowl. Mix until smooth and refrigerate until needed.
06 - Lightly toast the split brioche buns until golden.
07 - Spread a generous layer of garlic aioli on both halves of each toasted bun. Place a lettuce leaf and fried chicken breast on each bottom half. Arrange tomato slices and pickles as desired. Cap with the remaining bun halves and serve fresh.