Chilled Celery Soup

Directions

1. 1
   Wash leek well in a bowl of cold water, then lift out and drain.
2. 2
   Cook celery, onion, and leek in oil in a 6-quart heavy pot over moderate heat, stirring occasionally, until softened, about 10 minutes.
3. 3
   Add remaining ingredients (vegetables may not be fully submerged) and simmer, covered, until celery and potatoes are tender, about 10 minutes.
4. 4
   Puree in batches in a blender until smooth (use caution when blending hot liquids), then force through a fine-mesh sieve into a bowl, pressing hard on solids, then discarding them.
5. 5
   Set bowl in a larger bowl of ice and cold water.
6. 6
   Let stand, stirring occasionally, until cold.
7. 7
   Season with salt.
8. 8
   Serve chilled or at room temperature.