Step 1

1 In a large pot over medium-high heat, bring the potatoes, leeks, water and salt almost to a boil, then reduce the heat to medium-low and simmer, stirring occasionally, for about 45 minutes

Step 2

2 Set aside to cool for at least 10 minutes

Step 3

3 Strain the vegetables, reserving the cooking liquid

Step 4

4 Transfer the vegetables and a little of the cooking liquid to a blender or food processor and puree, or pass only the vegetables through a food mill

Step 5

5 Return the puree to the pot and add as much of the cooking liquid as necessary to achieve the desired consistency, from 6 to 8 cups

Step 6

6 Stir to combine

Step 7

7 (May cover and refrigerate overnight

Step 8

8 )

Step 9

9 To serve, return the soup to a gentle simmer and stir in the cream

Step 10

10 Do not boil after adding the cream

Step 11

11 Sprinkle with parsley or chives

Step 12

12 VARIATION

Step 13

13 To add a watercress puree: Remove and discard the stems from 2 bunches of watercress

Step 14

14 Cook the leaves in 2 quarts (8 cups) boiling, salted water for 2 minutes

Step 15

15 Drain the watercress in a colander and rinse immediately with cold water

Step 16

16 Place in a blender with about 1/2 cup water and blend until smooth

Step 17

17 Stir into the finished soup just before serving

Step 18

18 (May substitute 6 ounces fresh spinach leaves for the watercress

Step 19

19 )