2 1/2 pounds leeks (about 8 medium)
1 1/2 tablespoons olive oil
2 tablespoons minced fresh chives
1 tablespoon chopped fresh thyme
3 pounds medium-starch potatoes (such as russets or Yukon gold), peeled and cut into 2-inch pieces (about 5 very large potatoes)
8 cups homemade chicken (page 269) or vegetable broth, or canned broth
1/4 teaspoon salt, or to taste
Freshly ground black pepper to taste
1/2 cup plus 2 tablespoons heavy cream
Cut the leeks in two crosswise to separate the dark green portion
from the white. Discard the greens or save for vegetable stock.
Cut the white part of the leeks in half lengthwise, and rinse out
any dirt between the layers, then cut the leek crosswise into 2-inch
In a large soup pot, heat the oil over medium-low heat. Add the leeks, chives, and thyme and stir. Reduce the heat to low, cover, and cook for 10 minutes, stirring occasionally. Add the potatoes, stir well, and cook for 2 minutes. Raise the heat to high and add the broth, salt, and pepper. (Be careful not to oversalt the soup if using canned chicken broth.) Bring to a boil, reduce the heat to low, and simmer, covered, for about 15 minutes, or until the potatoes are tender. Remove from the heat and let cool slightly.
In a food processor or blender, puree the soup in batches until smooth. Pour into a large bowl, stir in the cream, and taste for seasoning. Add salt and pepper if needed. Cover and refrigerate for at least 8 hours, or until well chilled. Serve cold with a generous teaspoon of Chive Puree swirled into each bowl.