Marinate the chicken (30 minutes to overnight):
In a large bowl, mix buttermilk, hot sauce, garlic powder, onion powder, paprika, salt, and pepper.
Add chicken breasts, making sure they’re fully coated. Cover and refrigerate for at least 30 minutes (overnight is best for flavor).
Prepare the coating (5 minutes):
In a shallow dish, combine flour, cornstarch, baking powder, and seasonings.
Coat the chicken (5 minutes):
Remove chicken from marinade, letting excess drip off.
Dredge each piece in the flour mixture, pressing firmly to coat. For extra crispiness, dip back into the buttermilk and dredge again (“double dredge”).
Heat the oil (5 minutes):
Pour vegetable oil into a heavy skillet or Dutch oven (about 1½ inches deep). Heat to 350°F (175°C). Use a thermometer for accuracy.
Fry the chicken (12–15 minutes):
Fry 1–2 pieces at a time, cooking until golden brown and internal temperature reaches 165°F.
Place cooked chicken on a cooling rack set over a baking sheet (keeps it crispy instead of soggy).
Make the hot honey (2 minutes):
In a small saucepan, warm honey with red pepper flakes (and vinegar if using) over low heat until fragrant. Do not boil.
Toast the buns (2 minutes):
Butter the brioche buns and toast in a skillet until golden.
Assemble the sandwiches (2 minutes):
Layer fried chicken, cheese slice, drizzle of hot honey, and any extras (pickles, coleslaw). Top with bun and serve immediately.