In a mixing bowl, whisk together buttermilk, egg, and 1 tablespoon of Cajun seasoning until well blended. Submerge chicken into the marinade and refrigerate for at least 1 hour or overnight.

In a large bowl, combine flour, remaining Cajun seasoning, cornstarch, and baking powder. Whisk together, then dredge marinated chicken in the mixture.

Heat oil in a heavy pot to 350°F (180°C). Prepare a wire rack with paper towels.

Fry chicken for 4-5 minutes on each side until golden brown. Transfer to wire rack to drain excess oil.

While chicken drains, toast buns lightly on a skillet or oven.

Spread mayonnaise on the bottom of each bun. Add crispy fried chicken, drizzle with jalapeño honey, and cap with the top bun.