Watercress Soup (Julia Child)

When measuring the watercress leaves and stems, pack them down in the measuring cup.

Simmer leeks, potatoes, water and salt together, partially covered, 40-50 minutes until vegetables are tender.

Stir in watercress and simmer 5 minutes.

While the watercress is simmering, you can prepare the following optional garnish if you wish: a small handful of watercress leaves boiled 30 seconds, rinsed in cold water and drained.

Mash the vegetables in the soup with a fork, or puree in blender. Correct seasoning.

Off heat and just before serving, stir in cream or butter by spoonfuls. Decorate with the optional watercress leaves.