Potato Soup
1 qt. milk 3 potatoes 2 slices onion 2 tablespoons butter 1 tablespoon Gold Medal flour 1/4 teaspoon celery salt or celery stalk 1 teaspoon salt Few grains pepper Few grains cayenne 1 teaspoon minced parsley Cook potatoes in boiling salted water until soft, drain, rub through puree strainer. Scald milk with onion and celery stalk; remove onion and celery and add milk slowly to potatoes, stirring constantly. Melt butter, add dry ingredients, stir until well mixed, then add to hot soup. Add also the minced parsley and cook one minute before serving.
A plain milk-based potato soup from a flour company's promotional book, thickened as much by the potato as by the spoonful of flour. Two small points of technique carry it.
- The hinge: strain the potatoes hotRub the potatoes through the strainer or ricer while they are still steaming, then add the scalded milk gradually. Cooled or overworked potato turns gluey, and a food processor will do the same in seconds — use a ricer, food mill or coarse sieve.
- Quantities1 qt. milk is 4 cups. Three potatoes means medium boiling or all-purpose potatoes, roughly 1 to 1 1/4 lb; a floury russet gives a lighter puree, a waxy potato a slightly gummier one.
- "Add dry ingredients" to the butterThis presumably means the flour, salt, pepper, cayenne and, if you are using it rather than the stalk, the celery salt — a small seasoned roux. Cook it a minute in the butter before it goes into the soup or the flour will taste raw.
- Two slices onionA couple of rounds off an onion, used only to perfume the milk and then removed. This is an infusion, not an aromatic base; do not be tempted to leave it in unless you want a more assertive soup.
- ScaldingBring the milk to just below a simmer, when it steams and shows bubbles at the rim, then hold it off the heat with the onion and celery for five to ten minutes. A heavy pan and moderate heat keep it from catching.
- Celery salt or celery stalkEither works; if you use the stalk, add about 1/4 teaspoon plain salt in its place so the seasoning does not fall short.
- Final cookingOne minute is enough once the roux is in — long enough for the flour to thicken, short enough that the milk does not scorch or curdle. Keep the heat gentle and stir.
- YieldAbout 6 cups (4 cups milk plus the potato puree), serving four to six as a first course or three as a light supper with bread.
Cook books issued by flour millers were a standard form of advertising in the early twentieth century, and the giveaway here is the single tablespoon of Gold Medal flour in a soup that scarcely needs it — the brand name is written into the ingredient list, as it is throughout these books. The recipe itself belongs to the school of mild, milk-thickened cream soups taught in American cooking schools around 1900: scald the milk with an aromatic, bind with a butter-and-flour roux, finish with parsley. Potato soup of this kind relied on the puree strainer, a wire-and-wood sieve that did the work a blender does now.