Anchovy Butter

A compound butter in the classic 4:1 ratio — four parts butter to one part anchovy. The only technical demand is that the anchovy be reduced to a paste fine enough to disappear into the fat.

• Keep the butter cool, not meltedPound or process with butter at cool room temperature so the emulsion stays intact. Melted butter will separate and the anchovy will settle out in grey specks.
• What "an ounce of anchovies" means hereRanhofer assumes whole salt-cured anchovies, which is why he tells you to wash them and wipe off the scales. Modern tinned fillets in oil are already cleaned and filleted; use about 1 oz drained, roughly 8-10 fillets, and expect a somewhat milder result.
• SaltPacked anchovies are far saltier than oil-packed ones. Use unsalted butter and taste before adding anything else — this butter is meant to season whatever it touches.
• Pounding versus processingA mortar gives the smoothest paste, but a small food processor works if you blitz the anchovies alone first, then add the butter in pieces. Scrape down often.
• The sieve is not optionalEven filleted anchovies carry fine pin bones and connective tissue. Pressing the finished butter through a fine sieve with the back of a spoon is what separates this from a coarse mash.
• Cayenne"A little" means a pinch; the original gives no measure. It is there for warmth behind the salt, not for heat you can identify.
• Yield and keepingA little over half a cup. Roll in parchment into a log, chill firm, and slice off coins as needed. It keeps about a week refrigerated and freezes well for several months.
• How it was usedSlices on grilled steak or broiled fish, spread on toast points for canapés, or whisked into a sauce off the heat to finish it.