1 teaspoon chile powder, plus 2 tablespoons extra for flour mixture
2 cups all-purpose flour
½ cup cornstarch
1 teaspoon paprika
1 teaspoon garlic powder
1 teaspoon schichimi (Japanese seven spice)
1 small head bibb lettuce, leaves separated
Directions
Make the gochujang mustard miso: In a small saucepan over medium heat, whisk together the miso paste, garlic, brown sugar, sesame oil and rice vinegar. Cook it until the miso dissolves and becomes fragrant, about 1 minute. Remove the saucepan from the heat and fold in the gochujang, mustard and water using a rubber spatula. Set the miso mixture aside; makes about 1 cup.
Make the Korean fried chicken: Combine the buttermilk, gochujang paste and 1 teaspoon of the chile powder. Add the chicken to the buttermilk brine and cover it with plastic wrap. Refrigerate for at least 4 hours, or preferably overnight.
Remove the chicken from the brine and transfer to a wire rack placed over a parchment-lined, rimmed sheet tray. Allow the chicken to sit at room temperature for at least 30 minutes to allow the salt to redistribute.
Pour enough oil in a 6-quart Dutch oven to reach a depth of 2 inches. Heat the oil until a deep-fry thermometer reads 375°. While the oil is heating, combine the 2 additional tablespoons of chile powder, flour, cornstarch, paprika, garlic powder and schichimi together in a large bowl.
Dredge the chicken in the flour mixture, making sure that every piece is evenly coated.
Fry the chicken in 2 batches, cooking the larger pieces first, until golden brown and crisp, or until an instant-read thermometer inserted into the thickest part of the thigh reads 155°, about 10 to 12 minutes. Transfer the chicken to a wire rack placed over a paper towel-lined sheet tray. Season it with salt while still hot, and serve it with the gochujang mustard miso and lettuce cups.