Cocka Leekie
(Scotland.) This is the oldest recipe for soup known, as it dates back to the fourteenth century. Wash and trim 1 dozen leeks, cut them in pieces half an inch long, discarding roots and tops, then fry them in 1 ounce of butter, with 2 stalks of celery and 1 carrot, cut fine. When brown but not burnt, add 1 1/2 quarts of chicken broth and 1 cup of cooked chicken, cut into dice. Simmer, covered, 2 hours, then add salt, pepper, and yolk of an egg, blended with a little of the broth, first, before adding to the soup.
A short, forgiving soup, but two instructions need attention: the egg yolk at the end and the two-hour simmer.
- The egg yolk is the hingeBlend the yolk with a ladle of hot broth first, as directed, then stir it back off the heat or over the barest heat. If the pot is boiling when it goes in, the yolk scrambles and the soup turns grainy.
- A dozen leeksA dozen leeks of the size sold today is a great deal; six to eight large modern leeks, trimmed of root and dark green tops, will give roughly the volume this soup wants. Split them lengthwise and rinse well between the layers -- grit hides there.
- Two hours is a long timeAfter two hours the leeks will have collapsed into the broth, which is how the older versions of this soup got their body. If you want distinct pieces of leek, hold back a third of them and add for the last fifteen minutes.
- Add the chicken lateThe cup of diced cooked chicken does not need two hours. Stir it in for the final ten minutes so it warms through without shredding to threads.
- Fry them brown but not burntMedium heat, about eight to ten minutes, stirring. The thin leaf ends catch quickly; a dark fleck or two is fine, a black one will flavour the whole pot.
- Broth quality decides the soupWith only leeks, celery, carrot and a little chicken, the 1 1/2 quarts of broth is the dish. A homemade stock, or a good low-sodium one, is worth the trouble; salt only at the end, as instructed, since the broth reduces slightly under the lid.
- YieldAbout 1 1/4 quarts after simmering -- four generous bowls, or six as a first course.
- The missing prunesMany traditional Scottish versions include a handful of stoned prunes towards the end of cooking, for a sweetness against the leeks, though their presence has long been argued over. This recipe leaves them out; add eight or ten in the last half hour if you want that version.
Cock-a-leekie is a standing soup of the Scottish kitchen, and the name is what it says: a boiling fowl (the cock) simmered with leeks, the leeks so thoroughly cooked that they thicken the broth. The claim here that it is "the oldest recipe for soup known" dating to the fourteenth century is the sort of flourish common in turn-of-the-century travel cookery and should not be trusted -- the dish is generally traced in print to eighteenth-century Scotland, and it was familiar enough by the early nineteenth century for Walter Scott to mention it. What is genuinely old is the method: a tough old bird, past laying, cooked long and slow with leeks from the kitchen garden. This version, written for a reader with a stockpot rather than a hen, substitutes ready-made broth and leftover cooked chicken.