Use a blender, not a food processor to purée this soup or it will become gummy.
3 large leeks (1 ½ pounds), white and light-green parts trimmed
1 medium clove garlic, minced
4 small Yukon Gold potatoes (1½ pounds), peeled
5 carrots, peeled
2 ½ cups chicken stock
1 ½ teaspoons salt
1/8 teaspoon; black pepper
2 cups milk, whole is best
Cooking spray
1. Coarsely chop leeks; place in bowl of cold water. Let stand 5 minutes to rid them of dirt and sand; lift out of water; drain in colander.
2. Spray bottom of small stockpot with oil spray; place over low heat. Add leeks and garlic; cover and cook, stirring occasionally, until leeks are wilted, about 12 minutes.
3. Cut 2 potatoes into small chunks; add to leeks. Slice 3 carrots into ¼-inch-thick rounds; add to vegetables along with stock, salt, pepper, and 2 cups water. Cover partially, raise heat to high, and bring to a boil. Reduce heat to medium low; cook until vegetables are tender, 15 to 20 minutes. Remove from heat, stir in milk, and purée in blender until smooth. Let stand until cool; refrigerate until cold.
4. Meanwhile, finely julienne remaining 2 potatoes and 2 carrots; place in a small pot of boiling water. Boil until just tender, 2 to 3 minutes. Drain; add carrots and potatoes to puréed soup. Serves 6.