Leek and Potato Soup (Potage Parmentier)

10yellow Finn potatoes, peeled and sliced or diced4-6tablespoons milk or cream
1bunch leeks, trimmed, cleaned, then thinly sliced2-3tablespoons minced parsley or chives
Salt


Put potatoes, leeks, salt to taste, and 8 cups of water in a large saucepan over medium heat and simmer, partially covered, until vegetables are tender, 40-50 minutes. Mash vegetables in the soup with a fork, or pass the soup through a food mill or ricer. Correct seasoning with salt. Off heat, just before serving, stir in the milk or cream by spoonfuls. Sprinkle servings with the minced herbs.