Ingredients

  • 3 tablespoons extra-virgin olive oil
  • 1 large leek, white and tender green parts only, thinly sliced
  • 2 cups low-sodium chicken broth
  • 2 cups water
  • One 8-ounce Yukon Gold potato, peeled and sliced 1/3 inch thick
  • 1/2 pound watercress, coarsely chopped (5 cups)
  • 1 cup whole milk
  • 1 cup skim milk
  • Salt and freshly ground pepper
  • 1/2 European cucumber, peeled
  • 1 tablespoon unseasoned rice vinegar

Method

  • In a large saucepan, heat the olive oil.
  • Add the leek and cook over moderate heat, stirring, until softened, 3 minutes.
  • Add the broth and water and bring to a boil.
  • Add the potato, cover and simmer over low heat until tender, about 15 minutes.
  • Add the watercress and cook until bright green, about 2 minutes.
  • Working in batches, puree the soup in a blender.
  • Return the soup to the saucepan.
  • Add the whole and skim milk and season with salt and pepper; keep warm.
  • Meanwhile, trim the peeled cucumber to form a rectangle.
  • Cut the cucumber crosswise into very thin slices.
  • In a medium bowl, combine the rice vinegar with a large pinch of salt.
  • Add the cucumber slices and toss well.
  • Let stand until they have softened, about 5 minutes.
  • Ladle the soup into bowls.
  • Garnish with cucumber slices and serve.