Lucas Herrings

Harengs Lucas (Lucas Herrings) teaches controlled desalting. The soaking is the dish, not preliminary housekeeping: water removes the cure's hard edge, milk draws out the remaining salt and rounds the fish, and careful drying lets the mustard mayonnaise cling rather than slide away. Before you reach for a whisk, know this one true thing: the herring should remain pleasantly salty. You're taming the cure, not erasing it.

The original entry assumed whole fine salted herrings, a commis to raise clean fillets, and someone free to beat the sauce for service. At home, buy ready-to-eat salt-cured fillets and use pasteurized yolks because the dressing remains uncooked. The filleting was brigade scaffolding and can go; the water-then-milk sequence, the two-yolk emulsion, and the exact five-parts-oil to two-parts-vinegar measure are the dish and must stay. I translate its single dessertspoon of chopped chervil and gherkin as two level teaspoons total, split evenly, and set four fillets for four starter portions. One cook, one stove, one evening, and the stove stays cold.

When it's right, the firm silver herring wears a pale ochre sauce, glossy with oil, green with chervil, and sharp enough to wake the appetite without bullying the fish. Dry the fillets thoroughly before they meet that sauce. This is the step that matters most.