Melt the butter in a large pan and
gently fry the onions, leek and potatoes for 5 minutes, stirring
frequently. Stir in the stock and season with
salt and pepper. Cover and simmer gently for 40
minutes. Cool slightly, then puree in a
blender or food processor. Return the soup to the pan. Add the milk and reheat. Taste and adjust the seasoning. Serve hot with swirls of cream and
garnished with the chives.
This soup is good served with