1. Bring water to boil in medium saucepan. Add carrots and ginger; cook, covered, over medium-low heat 25 minutes or until tender; chill in covered saucepan.
2. Purée carrots and liquid in food processor or blender until smooth. Pour into a bowl; stir in buttermilk and salt. Swirl in a little extra to decorate.
Total time does not include chilling