Shallot Butter

A compound butter from Ranhofer's repertoire of finishing butters, meant to be whisked into sauces or spread on grilled meat and fish rather than served as a dish in itself.

• QuantitiesHalf a pound is 225 g, two American sticks. Twelve shallots is roughly 4-6 oz peeled, depending on whether you get the small French type or the large single-lobed ones now common.
• The pounding stepThe mortar work is what makes this different from stirring chopped shallot into butter: bruising the shallots releases their juice so the flavour goes through the whole mass. A food processor does it, but pulse rather than run, or the butter warms and separates.
• SievingRubbing through a sieve, not straining, is the point here. It removes any coarse or fibrous pieces and leaves a smooth butter that will melt cleanly into a sauce without specks. A drum sieve or a fine-mesh strainer and a stiff plastic scraper both work; the butter must be soft, not melted.
• Raw or blanchedRanhofer leaves the shallots raw, which gives a sharp, slightly sulphurous bite. If the butter is to be eaten cold on bread or under a fish, some cooks blanch the minced shallots a minute and dry them well to take the edge off.
• SaltThe recipe does not specify salted or unsalted butter. Season to taste after sieving if you plan to serve it cold.
• Yield and keepingRather more than the half pound of butter you started with, allowing for what is lost at the sieve; enough to finish several sauces. Roll it in parchment into a log and it keeps a week refrigerated or three months frozen; slice off coins as needed.
• Using itAdd it off the heat, in cold pieces, swirled in at the end. If the sauce boils after the butter goes in, the emulsion breaks and you get a greasy slick with shallot suspended in it.