Crispy Chicken Salad with Buttermilk Blue Cheese Dressing

Heat oven to 400 degrees F. Line a rimmed baking sheet with nonstick foil. Place the cornflakes in a shallow bowl. Using 1/4 cup of the buttermilk, brush the chicken breasts on all sides, then season with the cayenne, 1/2 teaspoon salt and 1/4 teaspoon pepper. Coat the chicken in the cornflakes, pressing gently to help them adhere, and place on the prepared baking sheet. Bake until cooked through, 15 to 20 minutes. Meanwhile, make the dressing: In a medium bowl, whisk together the sour cream, vinegar, and remaining 1/4 cup buttermilk. Stir in the blue cheese and 1 tablespoon chives. Divide the lettuce and tomatoes among plates. Spoon the dressing over the top. Sprinkle with the remaining tablespoon chives and additional blue cheese, if desired. Serve with the chicken.