Step 1

For best results, be sure to use a very ripe avocado.

Step 2

Combine buttermilk, lime juice, oil, sugar, 1/2 teaspoon salt, and 1/2 teaspoon pepper in medium bowl. Add avocado and mash into dressing with fork. Stir in chicken until fully combined. Season with salt and pepper to taste.

Step 3

Place heaping 1/2 cup chicken salad on each of 4 bread slices. Divide and arrange lettuce and tomatoes over chicken salad, then top with remaining bread slices. Serve.