Finnan Haddie and Watercress Soup

1. 1

   In a kettle cook the potato, peeled and diced, and the onion in 4 tablespoons of the butter over moderately low heat, stirring occasionally, until the onion is softened.

2. 2

   While the vegetables are cooking, put the finnan haddie in a deep skillet just large enough to hold it, add the milk, the remaining 2 tablespoons butter, and 2 cups water, and bring the liquid to a simmer over moderate heat.

3. 3

   Turn the finnan haddie and cook it, covered, at a bare simmer for 3 minutes.

4. 4

   Transfer the finnan haddie with a slotted spoon to a plate.

5. 5

   To the kettle add the fish poaching liquid and 2 cups water and simmer the mixture, covered, until the potatoes are soft.

6. 6

   Stir in the watercress and simmer the soup, uncovered, for 3 minutes.

7. 7

   In a blender puree the soup in batches until it is smooth, return it to the kettle, and stir in the lemon juice and salt and pepper to taste.

8. 8

   The soup and the finnan haddie may be prepared 1 day in advance and kept separately, covered and chilled.

9. 9

   Heat the soup, stirring, until it is hot, ladle it into heated bowls, and garnish each serving with some of the finnan haddie, flaked.

* Per serving · 4 servings · Values may vary.