Kryddersild

December in Copenhagen comes fast. The streets go dark by four in the afternoon, the windows fog from the inside, and the candles come out in every kitchen. This is julefrokost season, the long, slow Danish Christmas lunches that stretch across whole afternoons, and at the beginning of every one of them sits a plate of herring.

Kryddersild is the deepest of the herring jars. Not the sharp pickled one. Not the curry one with its yellow sauce. This is the aromatic one, cured for weeks in a brine of allspice and clove and bay until the fish takes on the dark, spiced warmth of something that belongs on a winter table. The work is mostly in the waiting. You make the brine, you pour it cold over salt-cured herring, and you let time do the rest. The season decides when you start. If you want kryddersild for your Christmas table, you begin in late November.

I want you to understand one thing before you shop for ingredients. This recipe begins with saltsild, herring that has already been salt-cured for months at the fishmonger. You don't cure it from raw at home. Your job is the spiced brine, the second stage, the one that turns already-preserved fish into kryddersild. Most Danish fishmongers and the better supermarkets sell saltsild through autumn and winter. Outside Denmark, look for salt-cured herring or matjes fillets in a Nordic or eastern European shop. Then you give it time. A week is the minimum. Two weeks is better. Three is how your grandmother would have done it.

Serve it cold on dark rugbrod with a spoonful of sour cream, raw red onion rings, and whole capers. That's the classical plate, and it hasn't changed in a hundred years because it doesn't need to. This is how we greet each other at the table in December.