Anchovy Butter or Paste

Ingredients

• 2 dozen anchovies
• 0.5 lb fresh butter

Method

Rinse the anchovies under cold water, then lay them on paper towels and pat dry completely — moisture is the enemy of shelf life here. Split each fish lengthways with your thumbnail, working from gill to tail, and lift out the central bone. You'll feel it come free cleanly if the fish are fresh enough. Discard any that crumble or smell off-note (they've begun to break down). What you want are firm fillets with a translucent, almost glass-like appearance.

Pound the dried fillets in a mortar and pestle until they collapse into a rough paste — this takes about five minutes of deliberate work. Don't rush it into powder; you're looking for visible flecks still suspended in oil. This texture matters because it keeps the emulsion stable when you add the butter. Soften the butter to room temperature (around 18°C), then add it in walnut-sized pieces, working each portion in thoroughly with the pestle before adding the next. The friction and agitation of pounding achieves emulsification, forcing the fat and salt-cured fish protein into a cohesive cream. You'll see the colour shift from rust-brown to a mottled putty-beige as the butter distributes.

Press the entire mixture through a fine sieve, using the back of a wooden spoon to force it through. This removes any bone fragments or sinew that the pounding missed, and it refines the texture to something almost suede-like — closer to a proper paste than a rough spread. The final product should be homogeneous and spreadable at room temperature.

For preservation, the traditional method is sound: preserving anchovy butter under a seal of clean animal bladder (or in practice today, a tight layer of cling film pressed directly onto the surface) prevents oxidation, which browns it and turns the flavour rancid. Store in earthenware or glass pots in a cool larder or the refrigerator. A 5cm layer of clarified butter poured over the top is the modern equivalent of the bladder seal — it's insurance against air exposure. Kept this way, the butter will hold for three months. Use it cold, spread thin on bread, or melt it into hot pasta or fish stock where it becomes invisible umami.