Cream of Potatoes Soup

Description
In Romanian: Supa de cartofi (crema)

Ingredients

 * 2 qts / 2 l water
 * 1 lb / 500 g potatoes
 * 1 onion
 * 1 cup sour cream or yogurt
 * 1 teaspoon flour
 * 1 tablespoon chopped parsley
 * 1 teaspoon butter
 * salt
 * toasted bread

Directions

 * 1) Boil the cubed potatoes with the finely chopped onion.
 * 2) When they are done, strain.
 * 3) Sieve the potatoes and thin with some of the boiling liquid.
 * 4) Add salt and set to boil.
 * 5) When the soup starts to boil, add the sour cream or yogurt well mixed with the flour.
 * 6) Let boil for a minute or two, add the chopped parsley and butter.
 * 7) Serve with toast.