Mix salt, sugar, and baking powder in a small bowl. Season chicken all over with mixture. Chill uncovered on a wire rack set inside a rimmed baking sheet, at least 2 hours and up to 1 day.

Whisk flour, cornstarch, garlic powder, onion powder, paprika, mustard powder, cayenne, and 2 teaspoons coarse kosher salt in a medium bowl. Whisk egg, buttermilk, bourbon (if using), and hot sauce in another medium bowl. Working with one piece at a time, dredge chicken in flour mixture, making sure to work into crevices. Shake to remove excess; return to rack. Drizzle 3-4 tablespoons buttermilk mixture into seasoned flour and work in with your fingers until small clumps form. Dip chicken into remaining buttermilk mixture, allow excess to drip off, then dredge in flour mixture. Using fingers, press some flour clumps onto chicken so they adhere. Gently shake off excess; return to rack. Chill at least 10 minutes and up to 12 hours.

Pour enough oil into a large heavy pot to come a little less than halfway up sides. Heat over medium-high until thermometer registers 365°F / 185ºC. Working in batches, fry chicken, turning every so often and adjusting heat to maintain a temperature of 350ºF /175ºC, until deep golden brown, 5–7 minutes per batch. Transfer to a wire rack set over paper towels to drain.

Add cabbage to a large bowl and toss with 3-4 tbsp. Basil Green Goddess Dressing until lightly coated. Taste for seasoning. Best if allowed to sit for at least 30 minutes.

Spread some basil green goddess dressing over cut sides of lightly toasted buns buns. Build sandwiches with pickles, fried chicken, slaw, and a few shakes of hot sauce, if desired.