Green Butter for Croûtes à la Française

Method

Put into a stewpan a bunch of tarragon and chervil and one eschalot, and just cover with cold water; add a pinch of salt and a tiny bit of soda; bring to the boil, strain off, press away any water, and put it in the mortar with four boned anchovies, two French gherkins, a dessertspoonful of capers, a saltspoonful of Marshall’s apple green, two hard-boiled yolks of eggs, a tiny dust of cayenne, and a quarter of a pound of butter; pound all together till smooth, pass through a fine wire or hair sieve, and use. This is sufficient for twelve croûtes.

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