Sauce Finiste

A quick browned-butter tomato sauce of the kind kept in the fish-and-meat chapters of turn-of-the-century American cookbooks. It comes together in about five minutes and depends almost entirely on how far the butter is taken.

• The hinge: browning the butterMelt the butter over medium heat and let the milk solids go a true hazelnut brown, swirling the pan so they colour evenly. Stop a shade before you think it is ready; carryover heat in the pan will darken it further, and burnt solids turn the whole sauce bitter.
• Mustard means dry mustardIn a book of this period an unqualified "mustard" in a sauce is most likely powdered mustard rather than a prepared jar. Half a teaspoon of dry mustard suits; if you substitute prepared mustard use about a teaspoon and expect added vinegar.
• Stewed and strained tomatoesThis is tomato pulp cooked down and pushed through a sieve to remove skin and seed -- roughly what is sold as passata or strained tomatoes. Three-quarters of a cup of canned tomato purée thinned slightly with water is a fair stand-in; tomato paste is far too concentrated.
• Add the tomato off the heatCold liquid hitting hot brown butter spatters hard. Pull the pan aside, stir in the tomato and seasonings, then return it to low heat just long enough to warm through.
• SeasoningNo salt is listed. Taste and salt at the end, after the Worcestershire has gone in, since that already brings salt and anchovy.
• Yield and servingRoughly a cup, given the 3/4 cup of tomato plus the butter. It suits broiled or fried white fish, grilled steak or chops; keep it thin and pour it around the plate rather than over, so it does not soften a crisp surface.
• Holding and reheatingBrowned butter sauces separate if held hot for long. Make it at the last minute, or reheat very gently and whisk to bring it back together.