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Mushrooms, Pickled, Sauce Of
To half a pint of brown gravy add a table-spoonful of good mushroom ketchup, some pickled mushrooms, and a little of their liquor. Put the above ingredients into a saucepan, set it over the fire, and stir in an ounce and a half of butter, blended with a tea-spoonful of flour. It should not boil, but when thick, like smooth cream, serve over roast or broiled fowls. Time, about ten minutes.
A butter-thickened gravy that leans entirely on the quality of the two mushroom preserves in it. The whole technique is in one line: it should not boil.
- Half a pintCassell's is working in imperial measure, so half a pint is 10 fl oz, or about 1¼ US cups.
- Brown gravyIn period usage this generally means a made sauce — browned flour and butter let down with strong meat stock and simmered until glossy — rather than pan drippings alone. A good reduced brown chicken or veal stock, lightly thickened, stands in for it.
- Mushroom ketchupA thin, dark, salty liquid of salted mushrooms pressed and spiced, closer to Worcestershire or a mushroom soy than to anything tomato. It is still sold in Britain; a splash of soy plus a little mushroom soaking liquor gets close.
- Pickled mushroomsPeriod pickled mushrooms were small buttons in spiced vinegar or brine, firm and quite sharp. Commercial marinated mushrooms in oil are a different thing — drain and rinse them, and taste before adding much of the jar liquor, which may carry olive oil and herbs the sauce does not want.
- The butter and flourAn ounce and a half of butter rubbed with a teaspoon of flour is a beurre manié — about 3 tablespoons butter to a teaspoon of flour. Work it smooth and cold, then whisk it in in pieces off a hard heat so it emulsifies rather than melts out.
- Do not boilThe instruction is the whole point. Once a butter-finished sauce boils the emulsion is liable to break and the fat separates into slicks; hold it just below a shiver until it coats a spoon like thick cream.
- Salt lastKetchup, pickle liquor and reduced stock are all salty. Season only at the end, after the butter has gone in and the flavour has settled.
- TimingTen minutes is generous. Once the gravy is warm the butter goes in over two or three minutes; longer sitting on the heat only risks the split it warns against.
Mushroom ketchup was one of the great English store-cupboard liquids of the eighteenth and nineteenth centuries, made in autumn when field mushrooms were cheap: layered with salt, left to weep, then the black liquor strained, spiced with mace and pepper and boiled down to keep. Along with walnut ketchup and anchovy essence it did the work that stock cubes and bottled sauces do now, giving depth to a gravy in a kitchen with no refrigeration. Cassell's places this among the sauces for roast and broiled poultry; using both the ketchup and the pickled mushrooms in one pan puts the preserved liquid to work for depth and the pickled buttons for texture and a sharp note against the butter.