Nashville Hot Chicken

Place 1-gallon resealable plastic bag in large bowl. Add chicken to bag. In another bowl, whisk 5 cups water, hot sauce, 2 tablespoons sugar, 2 teaspoons garlic, and 3 tablespoons salt until salt dissolves. Pour over chicken; seal bag. Refrigerate 5 to 8 hours. Fit wire rack into foil-lined rimmed baking sheet. In 12-inch cast-iron skillet, heat oil on medium-high until 325 degrees F on deep-fry thermometer. While oil heats, place flour in large dish and buttermilk in large bowl. Drain chicken. Dredge 5 pieces chicken in flour. Dredge pieces in buttermilk, letting excess drip off, then in flour again, shaking off excess. Place each piece in hot oil. Cook 12 to 18 minutes, or until chicken is cooked (165 degrees F) and deep golden brown, turning and adjusting heat to maintain oil temperature. Transfer cooked chicken to rack; sprinkle with 1/4 teaspoon salt. Repeat with remaining chicken. In bowl, combine cayenne, paprika, remaining 2 teaspoon sugar, 3/4 teaspoon garlic and 1/2 teaspoon black pepper. Ladle 1/3 cup hot oil from skillet into bowl with spices. Stir well. To serve, brush chicken generously with spice paste.