Cornflakes in the coating means "fried" chicken turns extra-crisp—and stays that way for hours after cooking. Serve with Buttermilk Oat Waffles for an extra-fun chicken dinner.
Whisk together buttermilk, mustard, 2 teaspoons salt, and pepper in a shallow dish. Add chicken. Cover and refrigerate at least 3 hours and up to overnight.
Preheat oven to 425 degrees. Pulse cornflakes into coarse crumbs in a food processor. Transfer to a bowl; stir in flour, remaining 2 teaspoons salt, and oil.
Place a wire rack on a baking sheet. Remove chicken from buttermilk mixture, allowing excess to drip off. Working with a few pieces at a time, dip in eggs, then coat with cornflake mixture, patting to adhere. Place chicken on rack. Drizzle tops with more oil.
Bake chicken, rotating sheet once, until golden brown and cooked through, about 35 minutes (if browning too quickly, tent with foil). Serve warm or at room temperature.