Copycat Fried Chicken Sandwich

Ingredients (15)

• + 1 cup buttermilk add to pantry
• + 2 teaspoons kosher salt add to pantry
• + 1 dash hot sauce, or to taste add to pantry
• + 1 tablespoon dry ranch dressing mix (such as Hidden Valley Ranch®) add to pantry
• + 4 (5 ounce) skinless, boneless chicken breast halves add to pantry
• ✓ 1 ⅓ cups all-purpose flour
• ✓ 2 tablespoons cornstarch
• + ½ teaspoon freshly ground black pepper add to pantry
• + 1 ½ teaspoons cayenne pepper add to pantry
• ✓ 1 large egg, beaten
• + ¼ cup milk add to pantry
• + canola oil for frying add to pantry
• + 4 soft hamburger buns, toasted and buttered add to pantry
• + 6 tablespoons mayonnaise, or to taste add to pantry
• + 12 dill pickle slices, or to taste add to pantry