A two-stage desalting — water, then milk — is the whole method here; the frying and the potatoes are straightforward. Ranhofer assumes a hard-cured salt herring far saltier than most fish sold today.
- Know what you boughtSalt herring packed in dry salt or heavy brine genuinely needs the six-hour soak with several water changes. More lightly cured herrings sold today, such as matjes, are far less salty and can turn to mush and lose flavour if given the full treatment; taste a scrap after two hours and stop when it is pleasantly salty rather than harsh.
- Soak coldDo the water soak in the refrigerator, not on the counter. Six to eight hours at room temperature in a low-salt bath is exactly the condition in which spoilage bacteria wake up.
- The milk stageTwo hours in milk is not just further desalting — the milk softens the flesh and rounds off the sharp cured taste. Discard the milk afterwards; it will be salty and fishy and is of no use.
- Splitting the fishCut down the length of the back and open the fish flat; the backbone can be lifted out at this point if you prefer, though Ranhofer does not say to. The fine pin bones soften considerably in a hard-cured fish and can be left.
- FryingWipe the fillets genuinely dry or the butter will spit and the fish will steam. Herring is oily and cooks fast — two to three minutes a side in foaming butter over medium heat, skin side first.
- No. 2798, the potatoesThe cross-reference is to mashed potatoes finished with cream. Go easy on salting them until the herring is on the plate, since the fish brings its own.
- YieldOne split herring per person as a first course, two as a main. Ranhofer gives no quantity here.
- FinishingA squeeze of lemon or a spoonful of the browned butter from the pan over the top is in keeping.
Salt herring was the cheap protein of northern Europe for centuries — cured on the boat or at the quay, barrelled, and shipped inland where fresh sea fish never reached — and by the time Charles Ranhofer wrote The Epicurean (1894) out of his kitchen at Delmonico's it had a settled place on the fashionable table as well. The pairing with creamed potato is not Ranhofer's invention: salt herring over or beside potatoes is standard across the Dutch, German, Scandinavian and northern French repertoires, the bland starch existing precisely to absorb what remains of the cure. The second soak in milk and the frying in fresh butter are refinements that cost money and time, though the milk soak was also common domestic practice for salt fish. The book's habit of cross-referencing a garnish to another numbered entry — here No. 2798 for the potatoes — reflects its origins as a working professional's system rather than a book meant to be read straight through.