From My Carolina Kitchen
1 pound starchy potatoes, such as Idaho, peeled and cut into a large chunks
2 leeks, trimmed, well rinsed, and julienned
1 quart of water
Kosher salt and freshly ground white pepper
¾ cup heavy cream or crème fraiche
For a garnish: 3 tablespoons finely chopped fresh herbs, such as tarragon (my personal favorite), chives, or flat-leaf parsley
Combine the potatoes, leeks, and water in a large saucepan. Bring to a boil over high heat and add some salt and pepper. Reduce the heat and simmer gently until the potatoes and leeks are very soft, about 25 to 35 minutes, depending on the size of the potatoes.
Carefully puree the soup in a blender or a food processor (or pass through a food mill). Return to the saucepan. Add the cream and cook over low heat just until heated through. Adjust the salt and pepper and serve garnished with the fresh herb of your choice. Can be kept covered in the refrigerator for several days. Reheat gently. Serves 4 to 6.
Adapted from Bistro Cooking by Patricia Wells