Almost-Famous Chicken Sandwiches

INGREDIENTS

• 1 tablespoon malted milk powder
• Peanut oil, for frying
• 1/4 teaspoon dry mustard
• 3/4 cup all-purpose flour
• 1 tablespoon unsalted butter, softened
• Kosher salt and freshly ground pepper
• 1 large egg
• 1 sour pickle, cut into 8 slices, plus 1 tablespoon pickle juice from the jar
• 1 tablespoon plus 1 teaspoon confectioners' sugar
• 4 soft hamburger buns, split
• 2 skinless, boneless chicken breasts (about 6 ounces each)
• 2 teaspoons white vinegar
• 1/4 teaspoon baking soda
• 1/4 cup whole-wheat flour
• 1/2 cup nonfat milk
• 1 teaspoon paprika