Kimchi-Brined Fried Chicken Sandwich

Ingredients

• For the brine:
• 100ml kimchi juice, drained from 1 jar of kimchi
• 225ml buttermilk
• 1 egg
• 3 medium cloves garlic, smashed
• 6g kosher salt
• 15ml soy sauce
• 35g gochugaru
• 15g coarsely ground black pepper
• 6 boneless, skinless chicken thighs
• For the kimchi mayonnaise:
• 1 cup drained kimchi, roughly chopped
• 150g mayonnaise
• For the sauce:
• 125ml vegetable or canola oil
• 2 medium cloves garlic, smashed
• 35g gochugaru
• 25g gochujang, Korean chili paste
• 12g honey
• 10g apple cider vinegar
• 10g soy sauce
• Water, as needed
• For the spice mixture:
• 15g gochugaru
• 5g coarsely ground black pepper
• 12g sugar
• 15g black sesame seeds
• 10g kosher salt
• For the dredge:
• 225g all-purpose flour
• 75g cornstarch
• 8g baking powder
• 7g coarsely ground black pepper
• 35g black sesame seeds
• 15g garlic powder
• 6g kosher salt
• To Cook and Serve:
• 2L peanut oil
• 6 soft buns, such as potato rolls, toasted in butter, or 6 black sesame biscuits
• Finely shredded cabbage
• Sliced dill pickles

Directions

1. Make the brine by whisking together the kimchi juice, buttermilk, egg, garlic, salt, soy sauce, gochugaru, and black pepper in a big bowl. Add the chicken and turn the pieces through the mixture until coated all over. Scrape everything into a 1-gallon zipper-lock freezer bag, seal it, and chill for at least 4 hours and up to overnight, turning the bag now and then so the brine stays evenly distributed. While the chicken rests, prepare the kimchi mayonnaise, sauce, spice mixture, and dredge.
2. For the kimchi mayonnaise, pile the drained chopped kimchi onto the center of a clean kitchen towel, pull the towel up around it, and twist it closed. Squeeze firmly over the sink to press out as much liquid as possible. Add the kimchi and mayonnaise to a food processor, then pulse until the kimchi is chopped very fine and the mixture looks like tartar sauce. Spoon it into a container with a lid and refrigerate until needed.
3. For the sauce, add the oil, garlic, gochugaru, and black pepper to a small saucepan. Warm over medium heat, stirring the whole time, until it starts to sizzle, smells toasted, and the garlic is only beginning to turn light gold at the edges. Right away, pour it through a fine-mesh strainer into a clean pot or heatproof bowl. Throw away the strained solids and let the oil cool to room temperature.
4. Put the gochujang, honey, cider vinegar, soy sauce, and a couple tablespoons water in a blender. Start blending and gradually increase to full speed. With the blender running, stream in the chili oil so the sauce comes together. Add more water if it needs loosening; it should pour easily without seeming thin. Move the sauce to a sealable container and refrigerate until you are ready for it.
5. For the spice mixture, stir the gochugaru, black pepper, sugar, sesame seeds, and salt together in a small bowl. Cover it and leave it at room temperature.
6. For the dredge, add the flour, cornstarch, baking powder, gochugaru, black pepper, sesame seeds, garlic powder, and salt to a large bowl. Whisk until the mixture is evenly combined, then cover and set aside.
7. When it is time to cook, pour 2 quarts (2L) peanut oil into a wok or Dutch oven and bring it to 325 degrees F (163 degrees C), checking with an instant-read thermometer so you can hold the temperature there. Take 3 tablespoons of the marinade from the zipper-lock bag and add it to the dredge, then rub it in with your fingertips to make little shaggy bits. Lift 1 piece of chicken from the bag and let the extra buttermilk run back off. Set it in the dredge and toss to cover. Add the remaining chicken pieces the same way, one at a time, until all the chicken is in the bowl. Toss everything well, pressing with your hands so each piece gets a sturdy flour coating.
8. Piece by piece, move the coated chicken into a fine-mesh strainer and shake off the loose flour. Set the chicken on a wire rack placed inside a rimmed baking sheet. Once every piece is coated, carefully lower as much chicken as will fit comfortably in the wok or Dutch oven in a single layer. The oil should fall to 275 degrees F (135 degrees C); adjust the burner as needed so it stays between 275 to 300 degrees F (135 to 149 degrees C) while the chicken cooks.
9. Fry until the first side is a deep golden brown, about 6 minutes. Do not shift the chicken or peek at the underside until it has cooked for at least 3 minutes, since the crust can come loose if bothered too soon. Use tongs or a flexible fish spatula to turn the pieces carefully, then cook until the other side is golden brown and an instant-read thermometer pushed into the thickest part of a thigh reads at least 160 degrees F (71 degrees C), about 4 minutes longer. Transfer the fried chicken to a rack set in a rimmed baking sheet.
10. To assemble, spread kimchi mayo on the bottom and top bun, or on both halves of each biscuit. Put cabbage and pickles on the bottom half. Brush the chicken with sauce until it is coated, then dust it with the spice mixture. Set the chicken over the cabbage, close the sandwiches, and serve.