This soup is flexible and the ingredients can vary. I usually scan the refrigerator and see what I have on hand before I go shopping. It’s amazing what can happen with a slightly wilted bunch of watercress, some carrots from last night’s dinner, and other items on hand.
Good chicken stock will make better soup, but I have often made this with commercial stock, frozen or canned, which is perfectly adequate. Stock cubes are very salty and should be avoided if possible.