Fish Soup
Boil salmon, halibut, or cod in salted water until it flakes easily. Drain, remove skin and bones, and rub through strainer. To 1 pound of fish use 1 quart milk, boiled with an onion, for ten minutes; take out the onion, thicken milk with 1 tablespoonful butter and 2 tablespoonfuls flour cooked together. Add 1 teaspoonful salt and 1 saltspoonful pepper, and the fish. Let all come to a boil together, then serve.
A plain milk-based fish purée of the sort that filled the soup course in turn-of-the-century households. The technique is sound; only the units and a few timings need translating.
- SaltspoonfulA saltspoon is a quarter teaspoon. So the seasoning here is 1 teaspoon salt and 1/4 teaspoon pepper for roughly six cups of soup — taste and raise it, since the milk base swallows salt.
- Do not boil the fish to deathSalmon, halibut and cod flake at roughly 140F internal. Poach at a bare simmer for 8-12 minutes depending on thickness; hard boiling squeezes out moisture and leaves the purée grainy.
- The strainer stepRubbing through a sieve with the back of a ladle is still the best method for a smooth texture — a food processor turns cooked white fish pasty and a blender can make it gluey. If you use a machine, pulse briefly.
- Infusing the milkTen minutes of boiling will scald milk onto the pan bottom. Bring it just to a shiver with a halved onion, cover, and hold off the heat for 10-15 minutes, then discard the onion.
- The roux1 tablespoon butter to 2 tablespoons flour is a lean, tight roux. Cook it two minutes without colouring, then whisk in the hot milk gradually; adding all at once with this ratio gives lumps.
- Final heating"Let all come to a boil" is more than needed once the fish is in; bringing it back to a simmer is enough.
- Yield1 pound of cooked fish and a quart of milk makes about 6 cups — four to six first-course servings. It thickens as it stands; loosen with hot milk rather than water.
Cream-thickened fish soups sat awkwardly between two traditions in American cookbooks of this period: the older English fish gravies and purées, and the New England chowder built on salt pork, potato and ship's biscuit. The white-sauce base, butter and flour cooked together and let down with infused milk, is the sort of béchamel that cooking-school teachers of Fannie Farmer's generation treated as the foundation of nearly every cream soup.