The warming kick of curry lends depth and zing to this creamy chilled soup. Thai basil, with a light anise flavor which pairs well with the curry, is pureed into the soup as well as frozen into lime juice ice cubes to serve as a cooling garnish. Zucchini can be substituted for yellow summer squash. The ice cubes should be made at least five hours, and up to four days, before serving. This recipe was developed by assistant editor Anna Stockwell for her story on cold yogurt soups.