Puree Jackson
(Paris.) Wash, parboil, and pare 6 large potatoes. Slice them, add 2 ounces of butter, fry lightly, then add salt, pepper, nutmeg, a bayleaf, some parsley, 2 ounces of chopped ham, 1 sliced onion, and 6 stalks of celery. Simmer for 3/4 hour. Press through a sieve, add 1 pint of white stock made from chicken or veal, and 1 pint of boiling milk, 2 ounces of butter, and the yolk of 1 egg, blended with a little of the milk. Stir well, add some bread, toasted and cut in dice, called croutons, and serve at once.
A French-style potato purée soup, thickened at the end with an egg yolk liaison. Two steps need attention: the vegetables must not scorch during the long simmer, and the soup must not boil once the yolk goes in.
- The yolk is the hingeBlend the yolk with a little of the hot milk, stir it into the soup off the heat, and keep the pan below a simmer from that point on. A boil after the liaison will curdle it into threads of scrambled egg.
- The simmer needs liquidThe recipe lists no liquid for the three-quarter-hour simmer, only butter and vegetables. Cover the pan and use a low heat, or add a splash of the stock at the start; potatoes and ham in butter alone will catch and brown long before 45 minutes are up.
- Parboil then pareThe recipe boils the potatoes before peeling; skins slip off more easily once the potato has been briefly boiled. It is optional now; peeling raw costs nothing in flavour.
- Sieve, do not blend hardA food mill or a drum sieve gives the intended texture. A stick blender or food processor works the starch in cooked potato into glue; if you use one, pulse briefly and stop.
- White stockStock from chicken or veal bones simmered without browning, so it stays pale. Unsalted commercial chicken stock is the nearest substitute, and salt only at the end since the ham is already salty.
- QuantitiesIf the pint is the imperial 20 fl oz, each pint of stock and milk is roughly 2 1/3 to 2 1/2 US cups; if US measure, 2 cups. Two ounces of butter is 4 tablespoons, used twice — once for frying, once for finishing.
- CroutonsThe recipe stops to explain the term, which suggests it was not assumed familiar. Diced bread toasted dry, or fried in butter, added at the table so it does not soften.
- YieldTwo pints of liquid plus the purée of 6 large potatoes makes something closer to 7 or 8 cups, enough for six or more as a first course.
This dish is docketed simply "(Paris.)" — a note that the recipe was collected there rather than a claim about its invention. Naming a purée after a person is often said to have been a French kitchen habit: soups were catalogued under proper names the way sauces were, and some of them are thought to commemorate a patron, a hostess or a colleague whose identity dropped away within a generation. No documented Jackson attaches to this one. What the recipe does show clearly is a French treatment of the potato as a soup base rather than a side: sweated in butter with ham, onion and celery, sieved smooth, then let down with white stock and milk and enriched with a yolk at the last moment. The closing gloss on croutons — "some bread, toasted and cut in dice, called croutons" — is addressed to an English-speaking household still being introduced to the French service it was starting to imitate.