In a large saucepan, soften the celery, leek, and garlic in the butter. Add the water, broth, potatoes, and celery salt. Bring to a boil and simmer for about 20 minutes or until the vegetables are tender.
In a blender, purée the soup until smooth. Strain. Refrigerate for 4 hours or until the soup is cold. Add broth, if needed, and adjust the seasoning. Pour into bowls or cups. Add an ice cube. Garnish with a dollop of whipped cream, some celery seeds, and leaves.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.