I was so excited to see a small wooden box of salt cod fillets at a supermarket a few weeks ago. I had no idea what to do with it but knew I’d find recipes in 18th-century cookbooks, since cod was ubiquitous in colonial times.

Enormous cod populations were what first drew Europeans to America, according to Mark Kurlansky, author of Cod: A Biography of the Fish That Changed the World.  As Francis Higginson, the first minister of Salem, Massachusetts, wrote in 1630:

The aboundance of Sea-Fish are almost beyond beleeving, and sure I whould scarce have beleeved it except I had seene it with mine owns eyes.

Basques had already been fishing for Atlantic cod off North American coasts for centuries, and they had learned how to salt-cure the fish. Soon New Englanders were doing the same, selling their fish in Europe, where there was a huge demand, and eventually in the Caribbean, where it was used to feed slaves.

Unfortunately, Atlantic cod was fished nearly to extinction, and while regulations are in place to help stocks recover, it’s unclear if they ever will. Salt cod is now often made from other white-fleshed fish, such as haddock, pollock, and Arctic cod.

Whatever the actual fish used, salt cod is still popular in Europe. It’s called baccalà in Italy, bacalhau in Portugal, and morue in France, where it is typically puréed with garlic, olive oil, and potatoes in a dish called brandade de morue. It’s also common in Spain, Greece, and Scandinavian countries, and in the Caribbean, where it goes by the name saltfish.

Salt cod seems to have fallen out of favor in the United States since colonial times, and not just because the fish is rarer. Perhaps people don’t want to go to the trouble of soaking it when fresh fish can be had. I admit that it doesn’t look very promising straight out of the box, but it’s really not difficult to turn these dry, salty slabs into a good meal.

Here are Amelia Simmons’s instructions for “dressing Codfish” from American Cookery (1796):

Put the fish first into cold water and wash it, then hang it over the fire and soak it six hours in scalding water, then shift it into clean warm water, and let it scald for one hour, it will be much better than to boil.

Lacking a fireplace, I followed a cold-water method, based on Hannah Glasse’s The Art of Cookery Made Plain and Easy (1747) and adapted with some help from modern chefs like David Tanis. Salt cod is usually soaked from 6 to 24 hours (or longer) to remove most of the salt, with the water changed periodically. Soak it too briefly and it will be inedibly salty, too long and it becomes tasteless. It’s also important to simmer rather than boil it. Cooked properly, it will be mild and slightly salty, with a chewier consistency than fresh cod.

In colonial times, cod was served mashed up with boiled parsnips or potatoes, or an egg sauce made from chopped hard-boiled eggs and  butter. I think parsnips, which food writer Mark Bittman calls “probably the best vegetable that never gets eaten,” go beautifully with this fish.

Salt Cod with Puréed Parsnips

1 pound dried salted cod*
3/4 pound parsnips
1 tablespoon unsalted butter
2 tablespoons cream or milk
1/2 teaspoon salt, or to taste

1. Rinse the fish well and cut it into three-to-four-inch pieces. Place them in a deep-sided pan and fill it with cold water just to cover the fish. Change the water every hour or two, draining and refilling the bowl at least three times. Then cover and refrigerate overnight (or about 12 hours).

2. In the morning, remove the fish from the pan and throw out the soaking water. In a large pot or kettle, bring enough water to cover the fish to a simmer, place the fillets in it, and simmer gently — do not let the water boil. After 20 minutes, remove the fish from the water and set aside. Mash slightly.

3. While the fish is cooking, prepare the parsnips. Peel them, remove any woody centers, and steam in a double boiler over boiling water until soft, about 15 minutes. Purée the parsnips in a food processor with the butter, cream or milk, and salt.

4. Serve the fish with the parsnips.

 *You can find salt cod at some supermarkets or at Italian, Portuguese, or Spanish delicatessens. If you’d like to buy salt cod made from a less threatened species of fish, check with your fishmonger.