1 medium onion, chopped
570 ml. vegetable stock
3 bunches of watercress, chopped
3 or 4 medium potatoes (These are just for thickening)
290 ml. milk ( I usually use semi-skimmed, you could also use soya milk)
salt and freshly ground black pepper
freshly grated nutmeg
Melt the butter, add the onion and cook over a low heat until soft. Add the potatoes and stock and simmer for a few minutes until the potatoes are tender.
Liquidise the soup with the watercress in a food processor or blender and push it through a sieve. Pour back into the pan.
Add the milk and season with the salt, pepper and nutmeg. Reheat, but try not to let it boil.
It looks special if you serve it with some chopped garlic chives.
( I adapted this from a recipe in "LEITH'S COOKERY BIBLE" - the original specified too many potatoes for my taste, I prefer to use more watercress and fewer potatoes).