Step 1: Begin by preparing your chicken. Take two large boneless, skinless chicken breasts and slice them horizontally to create four thinner cutlets. This ensures even cooking and a more manageable size for your burger.
Step 2: In a large bowl, whisk together the buttermilk, hot sauce (optional), 1 tablespoon of salt, 1 tablespoon of black pepper, and 1 tablespoon each of smoked paprika, garlic powder, onion powder, cayenne pepper, dried oregano, and dried thyme (this forms your initial spice blend for the brine).
Step 3: Add the chicken cutlets to the buttermilk mixture, ensuring they are fully submerged. Cover the bowl and refrigerate for at least 4 hours, or preferably overnight (up to 24 hours). This brining step is crucial for juicy, flavorful chicken.
Step 4: When you're ready to fry, set up your dredging station. In a shallow dish, combine the all-purpose flour, cornstarch, the remaining 2 teaspoons of salt, 1 teaspoon of black pepper, and the remaining 2 tablespoons of the spice blend (paprika, garlic powder, onion powder, cayenne pepper, dried oregano, dried thyme). Mix thoroughly.
Step 5: Remove the chicken from the buttermilk, letting any excess drip off. Do not rinse. Place one chicken cutlet into the flour mixture, coating it completely. Then, dip it back into the buttermilk mixture briefly, and finally, dredge it again in the flour mixture, pressing firmly to ensure a thick, craggy coating. Repeat with the remaining chicken.
Step 6: Heat about 3-4 inches of vegetable oil in a large, heavy-bottomed pot or Dutch oven over medium-high heat until it reaches 350°F (175°C). Use a thermometer to monitor the temperature; maintaining a consistent temperature is vital for perfectly cooked fried chicken.
Step 7: Carefully lower 1-2 chicken cutlets into the hot oil, ensuring not to overcrowd the pot. Fry for 6-8 minutes, flipping halfway through, until golden brown and cooked through (internal temperature reaches 165°F / 74°C).
Step 8: Remove the fried chicken to a wire rack set over a baking sheet to drain any excess oil. Season immediately with a pinch of salt. Repeat with the remaining chicken.
Step 9: While the chicken is frying, prepare your burger buns. Lightly butter the brioche buns and toast them on a griddle or in a pan until golden brown. This adds texture and prevents sogginess.
Step 10: Assemble your burger! Spread your favorite sauce (e.g., spicy mayo) on both halves of the toasted bun. Layer with fresh lettuce, a slice or two of tomato, pickles, and finally, the glorious, crispy fried chicken. Top with a slice of cheese if desired. Close with the top bun and serve immediately.