1. Prepare the Chicken

• In a bowl, whisk together buttermilk, garlic powder, smoked paprika, salt, and black pepper.
• Add the chicken pieces and coat thoroughly. Let them marinate for at least 30 minutes, or up to overnight for deeper flavor.
• In a separate bowl, mix flour, panko breadcrumbs, cayenne pepper, salt, and black pepper.
• Remove the chicken from the marinade, allowing excess buttermilk to drip off.
• Dredge each piece in the flour mixture, pressing firmly to create a thick coating.

2. Fry the Chicken

• Heat vegetable oil in a deep skillet or frying pan over 350°F (175°C).
• Fry the chicken in batches, cooking for 4-5 minutes per side until golden brown and crispy.
• Remove and drain on a wire rack or paper towels.

3. Make the Romesco Sauce

• If using fresh red bell peppers and cherry tomatoes, roast them at 400°F (200°C) for 20 minutes until charred and soft.
• In a food processor, combine roasted red pepper, roasted tomatoes, almonds, garlic, vinegar, smoked paprika, red pepper flakes, and olive oil.
• Blend until smooth, adding salt and black pepper to taste.

4. Prepare the Garlic Aioli

• In a small bowl, whisk together mayonnaise, minced garlic, lemon juice, salt, and black pepper.
• Set aside until ready to use.

5. Assemble the Sandwich

• Toast the brioche buns lightly for extra flavor and texture.
• Spread a generous layer of Romesco sauce on the bottom bun.
• Place the crispy chicken on top, followed by lettuce, tomato slices, and red onion.
• Spread garlic aioli on the top bun and close the sandwich.

6. Serve and Enjoy

• Serve immediately with extra Romesco sauce on the side.
• Pair with fries, a simple salad, or roasted vegetables for a complete meal.