01 - Whisk together buttermilk, salt, black pepper, garlic powder, and smoked paprika in a large bowl. Add chicken pieces, turning to coat thoroughly. Cover and refrigerate for at least 30 minutes, preferably overnight.
02 - Preheat oven to 425°F (220°C). Line a baking sheet with parchment paper and place a wire rack on top.
03 - Combine panko breadcrumbs, all-purpose flour, onion powder, dried thyme, cayenne pepper if using, salt, and black pepper in a shallow dish.
04 - Remove chicken from marinade, allowing excess to drip off. Dredge each piece in the breadcrumb mixture, pressing firmly to ensure adhesion.
05 - Place chicken skin-side up on the prepared wire rack. Drizzle olive oil evenly over the coated chicken pieces to enhance crispiness during baking.
06 - Bake for 35 to 40 minutes until the chicken is golden brown, crunchy, and reaches an internal temperature of 165°F (74°C). Allow to rest for 5 minutes before serving.