stock to boiling. Add potatoes, onion and leeks, cover and cook gently
until vegetables are very tender, about 45 minutes. Whirl in blender a
little at a time until mixture is very smooth. Stir in cream. Taste and
add salt and pepper if needed (over salt slightly since salt loses some
flavor on chilling). Chill very well.
with a little milk if it is too thick for your taste. Ladle into chilled
soup cups. Sprinkle each serving with chives.