Swiss Soup
2 pounds Jerusalem artichokes 3 stalks of celery 1 large onion 2 ounces butter 1 quart milk 2 bay leaves Peel the artichokes and throw them into vinegar and water; then put them with the onion and celery in a saucepan with the melted butter; cover the pan, and let the vegetables steam until tender, taking care they do not brown. When soft, add the milk, which must heat slowly but not boil; remove the onion and celery, and rub the rest through a strainer with a wooden spoon; put the puree back in the pan with the salt, pepper and the bay leaves; keep it hot, on the back of the stove for about half an hour. Before serving, remove the bay leaves, and stir in 1/2 cup of hot cream or one ounce of butter.
A straightforward sweated-vegetable puree that depends entirely on keeping the heat low: the artichokes must not colour and the milk must not boil. Everything else is technique you already have.
- Jerusalem artichokesSold now as sunchokes. They are knobbly tubers of a sunflower, unrelated to globe artichokes, and 2 lb yields roughly 1 1/2 lb peeled. Scrubbing hard and leaving the skins on is acceptable and saves considerable time.
- The vinegar and waterCut surfaces oxidise fast. A bowl of water with a splash of any vinegar or lemon juice holds them white until they go in the pan; drain them well or the soup turns sharp.
- Do not brownThis is the hinge. Buttered vegetables under a lid over low heat should sweat and collapse, not colour; browning gives a nutty flavour that fights the pale, sweet character the soup is after. Use a heavy pan and the lowest workable flame, 25-35 minutes.
- Milk that must not boilA quart is 4 cups. Boiled milk can catch on the bottom of the pan and taste scalded; heat it to steaming only. Warming it separately before it goes in gives you more control.
- StrainingA wooden spoon and a sieve was the standard method. A blender or stick blender does it in seconds, though passing the result through a sieve afterwards still catches bits of skin.
- The half hour on the back of the stoveThat is the bay infusing over residual heat, not further cooking. Modern equivalent: hold it barely below a simmer, covered, for 20-30 minutes, then fish the leaves out.
- SeasoningSalt and pepper appear in the method but not the ingredient list. Season after the puree comes together, when you can taste it, and expect the dairy to want more salt than you first think.
- YieldThe milk alone is 4 cups; with the puree and the cream, expect something closer to 7 or 8 cups, enough for six as a first course.
- One practical warningSunchokes store their carbohydrate as inulin, which many people digest poorly. Small bowls are wiser than large ones on a first acquaintance.
Jerusalem artichokes reached Europe from North America in the early seventeenth century and were widely grown before the potato displaced them; the "Jerusalem" is generally traced to a corruption of the Italian girasole, sunflower, and has nothing to do with the city. Why this puree should be called Swiss is less clear: many nineteenth- and early-twentieth-century soups carried national labels that signalled a style rather than an origin.