Soup - Cream of Potatoes

• 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

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