Slice the potatoes and onions thinly and put them in a saucepan with the shelled peas (weighed shelled), the lettuce and half the chicken stock. Bring gently to the boil, cover and simmer quarter of an hour.

Pour into a blender or liquidiser and blend to a puree.

Return to the rinsed out pan, reheat and simmer 5 minutes. Now add the cream and the lemon juice. Season well with salt and pepper, cool and chill. Serve well chilled.