You can make this classic French soup in many different ways. Leave the vegetables whole and cook them in water alone for the most rustic version, enriched only with a little butter at serving time. For an even richer, more elegant variation, puree the soup in a food mill, food processor or blender, then stir in about one cup (8 fl oz/250ml) light (single) cream and gently rewarm.

Chill that cream soup and you have a classic vichyssoise The hot puree is also good with some shredded Swiss or Cheddr cheese stirred in tat the last minute. In a large saucepan, melt the butter over medium heat. Add the leeks and saute just until they begin to soften, 3- 5 minutes. Add the stock and potatoes, bring to a boil, reduce the heat to low, cover and simmer until the potatoes are very tender, about 20 minutes. Season to taste with salt and white pepper. Ladle into warmed bowls and garnish with the chives.