Luxembourg Potato Soup (Gromperenzopp) - cooking recipe

Ingredients

4 -5 leeks, washed and chopped (1 1/2 cups)
2 tablespoons butter, divided
4 -5 potatoes, peeled and diced (3 1/2 cups)
3 cups water, boiling
3 cups milk
2 egg yolks
1/2 cup cream or 1/2 cup sour cream
salt & freshly ground black pepper
fresh parsley, for garnish (optional)

Preparation

Cut up the green stalks and roots from the leeks and wash well; you should have about 1 1/2 cups.
In a heavy saucepan or Dutch oven, melt the butter over low heat; add leeks and saute until soft and translucent.
Add diced potatoes and 3 cups boiling water; season with 2 teaspoons salt.
Cook 30 minutes so that potatoes and leeks are very soft.
Strain mixture through a sieve or put through a food mill, and return to pot.
Meanwhile, in a separate saucepan, heat milk to boiling; blend egg yolks into the cream or sour cream.
Stirring constantly, add milk, 1 teaspoon butter, then the egg and cream mixture.
Season with salt and pepper; garnish with parsley if desired.
Add salt and pepper and finely chopped parsley if desired.