Peel potatoes then dice. Add diced onion, chopped dill, salt and pepper. Pour boiling water over all ingredients. Boil for 10 minutes then add sour cream. Boil an additional 5 minutes. When cold, puree in blender about 1/2 or 3/4 of soup. Pour into soup tureen and add remaining soup. May be ladled at table into cream soup bowls.