You will need:
2 leeks, washed, drained well and sliced into rings (white and pale green part)500g approx Potato (peeled and diced)2 cloves of garlic crushedChicken Stock or Vegetable Stock (about 1 litre)1 bunch of watercress (washed and roughly chopped)1 Bay leafNutmegSeasoningParsley
Butter and Olive oil for frying and some Plain Yoghurt, or sour cream or cream.In a heavy bottomed saucepan melt about a tablespoon of butter with a tablespoon of Olive Oil, enough to just cover the bottom of the pan.
On a moderate heat add the leek and garlic and sweat for a few minutes and then add the potato and bay leaf and continue to sweat. A piece of greaseproof paper pressed onto the top of the vegetables will aid this process. Ensure that the heat is moderate so that the vegetables do not burn.
After about 20 minutes add the Chicken or Vegetable stock and bring to a low simmer for about 10 minutes. Add the watercress and simmer for a couple more minutes.
Remove the Bay leaf and blitz the soup in either a liquidiser or with a hand held wand. The consistency of the soup is up to you - lumpy and textured or smooth and silky! Season with salt, pepper and nutmeg to taste. Stir through plain yoghurt to taste, 150mls should be sufficient, but again to taste.
Reheat to just below boiling to serve. Chopped parsley can be either added to the soup or just sprinkled on the top, together with a swirl of yoghurt.