01 - Place chicken breasts between two sheets of plastic wrap and pound to 1/2-inch thickness using a meat mallet.
02 - In a large bowl, whisk buttermilk and hot sauce. Add chicken, turning to coat. Cover and refrigerate for at least 1 hour or up to overnight.
03 - In a shallow dish, combine flour, cornstarch, paprika, garlic powder, onion powder, salt, black pepper, cayenne, and thyme.
04 - In a separate bowl, whisk eggs and milk together.
05 - Remove chicken from buttermilk, letting excess drip off. Dredge in seasoned flour, then dip in egg wash, then dredge again in seasoned flour, pressing lightly to adhere.
06 - Heat oil in a deep skillet or Dutch oven to 350°F (175°C).
07 - Fry chicken in batches, without overcrowding, for 5–7 minutes per side or until golden brown and internal temperature reaches 165°F (74°C).
08 - Transfer to a wire rack or paper towels to drain. Let rest for 5 minutes before serving.