Caper Sauce
Two tablespoons of flour; one tablespoon of lemon juice; three tablespoons of capers; one-half cup of butter; one pint of boiling water; one-eighth teaspoon of pepper; onehalf teaspoon of salt. Beat the flour and butter to a cream, and add the boiling water. Set the mixture on the fire, and stir it constantly until heated to the boiling point; then put in seasoning, lemon juice and capers, and serve either in a separate dish or by pouring over the meat it is to accompany.
A butter-forward sauce thickened by the old beurre manié method rather than a cooked roux. It comes together in a few minutes and needs watching only at the end.
- The hinge: do not let it boil hardWith half a cup of butter to only two tablespoons of flour, the emulsion is fragile. Bring it just to the boiling point, stirring constantly, and pull it off; a rolling boil will break it and leave a slick of butter on top.
- Beat the flour and butter coldBeat the flour and butter before any liquid — "beat to a cream" means working softened butter and flour into a smooth paste before the water touches it. Lumps at this stage are hard to disperse later. Add the boiling water gradually, stirring.
- MeasuresThe pint is 16 fl oz / 2 cups, this being an American book. Half a cup of butter is 4 oz / 1 stick.
- ConsistencyThis is a thin, pourable sauce by modern standards, closer to a hot butter sauce than a béchamel. If you want it to coat, use three tablespoons of flour rather than reducing it, which will only concentrate the salt.
- CapersSalt-packed capers need a good rinse and a soak; brined capers need draining only. Either way, add them at the very end so they keep their texture, and taste before adding the half teaspoon of salt, as the capers may have supplied it.
- Lemon juice last, off the heatLemon juice at the end -- the recipe adds it after the sauce has reached the boiling point, along with the seasoning and capers, rather than at the start.
- Yield and servingRoughly two to two and a half cups, enough for six to eight. The traditional partner is boiled mutton or leg of lamb; it also suits poached fish, boiled tongue and salt-cured pork.
Caper sauce belongs to the long English tradition of serving boiled mutton with something sharp to cut the fat, and it was so firmly attached to that dish that nineteenth-century menus often simply printed "boiled leg of mutton, caper sauce" as a single item. The capers themselves are the unopened flower buds of Capparis spinosa, a Mediterranean shrub; they reach the northern kitchen only pickled or salted, which is why they were a reliable pantry staple long before fresh Mediterranean produce was. The Butterick company was a pattern and magazine publisher, and its cook book, like its dressmaking guides, was aimed at the middle-class household that wanted a competent version of the standard repertoire rather than anything novel.