Vermicular | Fried Chicken with Soy Vinegar Sauce

Ingredients

• 1 ⅓ lb chicken thigh, boneless, skin-on, butterflied
• 1 teaspoon sake
• 1 teaspoon soy sauce
• 1 teaspoon mirin
• 1 teaspoon kosher salt
• 1 teaspoon fresh ginger, grated
• 1 teaspoon garlic, grated
• ½ egg, beaten
• 3 tablespoons Japanese leek, white part only, coarsely chopped
• 2 tablespoons soy sauce
• 2 tablespoons black vinegar
• 1 tablespoon granulated sugar
• 1 tablespoon sesame oil
• 1 pinch Sichuan peppercorns
• 1 red chili pepper, seeded, finely chopped
• 3 tablespoons all-purpose flour
• 3 tablespoons potato starch
• 1 cup vegetable oil