Serves 6
2 bunches watercress
1 medium-sized onion
1 oz (25g) butter
1 lb (450g) potatoes
11/2 pints (900ml) chicken stock 1 bay leaf
salt and freshly milled pepper 1/2 pint (300ml) milk
2-3 tablespoons single cream
Pick off the leafy tops from the watercress and set aside a small handful for the garnish. Peel and finely chop the onion. Melt the butter in a large saucepan over low heat, add the onion and fry gently for 5 minutes to soften but not brown. Meanwhile, peel and cut the potatoes in even-sized chunks. Pour the stock into the pan, add the bay leaf and season with salt and pepper. Bring to the boil, add the potatoes, then lower the heat and simmer gently, covered, for 15 minutes, until potatoes are tender. Add the watercress and bring back to the boil. Draw off the heat, discard bay leaf and stir in the milk. Pass soup mixture through a food mill, or puree in an electric blender or food processor.
Return the soup to the rinsed pan. Reheat and check seasoning.
Draw off the heat, stir in the cream, and garnish with chopped watercress. Ladle the soup into warmed soup bowls and serve.
For chilled watercress soup, allow the pureed soup to cool, then chill. Stir in 1/4 pint (150ml) single cream.
Parsley soup: Use 2 oz (50g) fresh parsley in place of the watercress. Omit the bay leaf.