In a large mixing bowl, combine buttermilk, hot sauce, 2 teaspoons salt, 1 teaspoon pepper, and 1 teaspoon garlic powder. Add chicken pieces and turn to coat. Cover and refrigerate for at least 4 hours or overnight.

In another large mixing bowl, whisk together flour, cornstarch, paprika, garlic powder, onion powder, salt, pepper, cayenne, thyme, and oregano.

Remove chicken from buttermilk, letting excess drip off but leaving some coating on the chicken - this helps the flour stick. Do not pat dry.

Dredge each piece in seasoned flour on cutting board, pressing firmly to coat thoroughly. Shake off excess. Place on a wire rack set over a baking sheet and let rest for 20 minutes - this helps the coating adhere.

Heat 2-3 inches of oil in deep fryer or heavy-bottom pot to 325°F. Add butter to the oil for extra flavor. Use a meat thermometer to maintain consistent temperature.

Working in batches (don't overcrowd), carefully add chicken pieces using tongs. Fry dark meat (thighs, drumsticks) for 13-14 minutes, white meat (breasts) for 10-12 minutes, turning occasionally, until deep golden brown and internal temperature reaches 165°F.

Transfer fried chicken to a clean wire rack set over a baking sheet to drain. Do not place on paper towels - this makes the bottom soggy.

Let chicken rest for 5 minutes on cutting board before serving. The residual heat will finish cooking the inside while keeping the crust crispy.