Fried Chicken Sandwich with Slaw and Spicy Mayo

INGREDIENTS

• 1 garlic clove, finely grated
• 1/2 cup mayonnaise
• 1 tablespoon Louisiana-style hot pepper sauce
• 1/2 small red onion, thinly sliced
• 1 jalapeño, thinly sliced
• 4 cups thinly sliced cabbage
• 1/2 cup bread-and-butter pickle slices, plus 1/4 cup pickle juice
• 2 cups all-purpose flour
• 1 tablespoon ground black pepper
• 1/2 teaspoon kosher salt plus more
• 1 cup buttermilk
• 2 8-ounces skinless, boneless chicken breasts, halved crosswise
• Peanut or vegetable oil (for frying)
• 4 white sandwich rolls
• 2 tablespoons unsalted butter, room temperature
• A deep-fry thermometer