Anchovy Paste

This is a compound anchovy butter rather than the dark, cooked paste sold in tubes today. The whole thing depends on getting the fish smooth before any fat goes in.

• Which anchoviesThe original means whole salt-cured anchovies, sold packed in salt and still on the bone. Rinse the salt away, soak 10-20 minutes in cold water if they are very fierce, then pat dry and lift the fillets off the backbone with your thumb. Oil-packed fillets work if you drain them well, but they are softer and saltier per gram.
• "Time, about half an hour"That is the pounding, not any cooking -- nothing here is heated beyond melting butter. A dozen anchovies is a small quantity, so a mini food processor gets you there in a minute or two; finish by pressing through a fine sieve as directed, which is what removes the pin bones and gives the paste its texture.
• Equal weightsA dozen anchovies gives two dozen fillets. Weigh the cleaned, sieved flesh and match it with the same weight of butter, as the recipe directs. Unsalted butter is the sensible choice; the fish brings all the salt the mixture needs.
• Butter melted but not hotMelt it only to the point of softness and take it off the heat. Hot butter will thin the puree, and the mixture may separate as it cools rather than setting into a firm paste.
• Adjusting strengthThe note about less butter is the real control. A 1:1 ratio spreads easily on toast; halving the butter gives something closer to a seasoning you stir into sauces, gravies or a steak butter by the teaspoon.
• Yield and keepingPack it into a small jar, smooth the top, refrigerate, and use within a week; it is uncooked, so keep it cold. It also freezes well rolled in parchment.