Mock Bisque
Bring to a boil 1 pint of tomatoes, 1 bay leaf, and a sprig of parsley. Boil slowly for ten or fifteen minutes. Add 1 teaspoonful of sugar and 1/3 teaspoonful of soda, then press through a fine sieve and season with salt and pepper. Have ready a pint of milk, heat it in a double boiler and thicken with 1 tablespoonful of butter rubbed into the same amount of flour. Add the heated milk to the strained tomato, and serve immediately with croutons. If not ready to serve the soup, do not add the soda or mix the tomatoes, but keep hot until needed and serve as soon as fixed.
A cream of tomato soup built on a thin white sauce, with baking soda as insurance against curdling. Everything hinges on how the two hot liquids meet.
- The hinge: combine off the heat, at onceTomato acid curdles milk protein, and the risk rises the longer the mixture sits or boils. Have both hot but not simmering, pour together, and take it to the table immediately.
- Which into whichThe recipe adds milk to tomato; pouring the thickened milk slowly into the tomato while whisking gives a smoother result than tipping the two together at once.
- SodaThe 1/3 teaspoon of baking soda neutralises part of the tomato acid and will foam, so add it (as the recipe does, before sieving) in a roomy pan. Much more than this can make the soup taste soapy and dull the tomato, so measure it rather than eyeballing.
- A pint of tomatoesCanned tomatoes with their juice, 16 fl oz, near enough to a small (14-15 oz) can. Fresh tomatoes, peeled and chopped, work if they are ripe.
- Double boilerOnly there to keep the milk from scorching. A heavy saucepan over low heat does the same if you stir; scalded milk will spoil the flavour of the finished soup.
- The butter and flourOne tablespoon of each rubbed to a paste is beurre manié, whisked into the hot milk in pieces. It gives a very light body — barely more than a coating. Cook it a minute or two after it thickens so the flour loses its raw taste.
- Holding itThe final instruction is sound: hold the strained tomato and the thickened milk in separate pans over low heat, leave the soda out until the last moment, and bring them together only when the bowls are out.
- YieldAbout a quart, serving four as a first course. Croutons should be crisp and added at the bowl, not the pot.
"Bisque" was used in French cookery for shellfish soups, often thickened with rice or bread, and American cooks applied the word more loosely to smooth, cream-enriched soups - hence a "mock" version made with nothing but canned tomatoes and milk. Canned tomatoes were cheap and available year round by the turn of the twentieth century, which is what makes a soup like this practical in any season. Advice to add a pinch of soda, and to keep tomato and milk apart until the moment of serving, appears in a number of cookbooks of the period, which is why recipes of this type so often end, as this one does, with "serve immediately."