Marinate: Combine buttermilk, hot sauce (if using), and 1 tsp salt. Submerge chicken strips and refrigerate 4–12 hours (minimum 30–60 minutes if short on time). Drain and pat strips dry before dredging.
Mix dry dredge: Whisk together 2 cups flour, cornstarch, paprika, garlic powder, onion powder, salt, pepper, and cayenne in a wide rimmed dish.
Make optional wet batter: In a second bowl, whisk 1 cup flour, beaten egg, and very cold sparkling water (or beer) until smooth. Keep cold. (If skipping wet batter, simply dredge directly in seasoned flour.)
Dredge: Remove chicken from marinade and let excess drip. For craggy crust: dip each strip into wet batter, then press into dry dredge. For extra texture, double-dredge (back into wet batter then back into dry). Place dredged strips on a wire rack and rest 8–10 minutes to set.
Heat oil & prep: Pour oil into a heavy Dutch oven or fryer to 2–3" depth. Heat to 325°F (163°C) for the first fry. Use an instant-read thermometer for accuracy.
First fry (cook through): Fry in small batches at 325°F for about 4–6 minutes until the strips reach 155–160°F internal. Don’t overcrowd. Transfer to wire rack to drain.
Second fry (crisp): Increase oil temperature to 375–390°F (190–199°C). Return strips in batches for 45–90 seconds until golden and crisp. Final internal temp should be 165°F (74°C). Drain on wire rack.
Make the glaze: In a small saucepan over very low heat, melt butter (or butter + oil). Off heat, whisk in cayenne, smoked paprika, brown sugar, garlic & onion powders, salt, Worcestershire, and hot sauce. Taste carefully and adjust balance — more sugar to tame heat, more cayenne for kick. Warm gently to incorporate, do not boil.
Finish with glaze: Using a spoon or brush, liberally coat each hot strip with the cayenne-butter glaze. For an intense coat, quickly dunk strips into a shallow bowl of glaze (do this briefly to avoid sogginess) or brush on both sides.
Serve immediately: Plate with white bread or buns and dill pickle slices. Offer ranch or blue cheese and lemon wedges on the side.