I can’t say I blame the refrigerator. There’s little doubt, though: rudimentary preservation methods yielded our richest morsels. Bacon, gravlax, prosciutto, cured sausages of every description—these and many more are the results of pre-icebox innovation. It’s fitting, really; sagacity and determination deserves a delicious reward. And is there a happier discovery than the salt-cured and fat-preserved duck leg? The anonymous peasant who conceived of the method may have had necessity alone in mind, but let it be testament to his or her genius: despite a humming refrigerator, six months rarely passes in this kitchen without a dinner of duck confit.

If perhaps not with much else, in kitchens I deeply appreciate efficiency. Cooking and sealing a perishable in its own fat is a very efficient loop—from butchering to final preparation there is little waste and nothing extraneous. This is especially the case with a duck, which has a large volume of subcutaneous fat, but rather lean meat. Confit solves the imbalance. Begin by butchering a Pekin (Long Island) duck into five pieces: two legs, two boneless breasts and the carcass with wings still attached. Remove all the fat from the carcass, wings and breasts, and put it in a heavy pot or dutch oven over low heat. Set the still-fat-covered legs aside. The skinless breasts should be immediately grilled rare and eaten on a sandwich while the fat renders. The carcass should be made into stock.

Efficient, but there is a mathematical problem in beginning with a single duck. The volume of available fat on a typical duck is just shy of that required to completely cover two legs. Somehow, through the magic of multiplication, beginning with two or three ducks improves the fat-to-legs ratio. The other option: source butchered duck legs and rendered duck fat. This is the less authentic approach in that it represents an expediency in the efficient loop earlier described. It also means no delicious duck breast sandwich or stock. It should have no material effect on the finished confit; I cannot speak for the opinions of those souls anonymously credited with dreaming up confit.

With the two major components of confit now acquired—duck fat and duck legs—the process can begin in earnest. The legs must be cured. What ails them? Moisture and trace surface bacteria. Happily, nothing more complicated than salt and time is needed. Generously sprinkle each leg with salt, and snugly pack in a clean terrine, ceramic casserole or stainless bowl. This is also a good opportunity to introduce aromatics. I favor garlic, black pepper and thyme, although bay leaf and even cloves are traditional. Wrap the container tightly in plastic wrap and refrigerate for a minimum of two days.

One might use the time to ponder food safety, and by extension, the tactic at play here to ensure it. Food safety is a moving target governed by time, temperature, air and the presence of bacteria. That last one is what typically turns stomachs, but keep in mind that bacteria is ever-present, on and inside of virtually everything. Most of it only becomes hazardous after it is permitted to grow, which readily occurs in humid, oxygen rich conditions between 40 and 140 degrees fahrenheit. The good news is bacteria is easily destroyed in a number of ways. Salt, for instance, kills surface bacteria, which is the prime goal of the above curing period. What takes place next guarantees safety.

After the two-day curing period, the duck will have shed moisture, most evident by the somewhat darker and contracted appearance of the flesh and fat. It will also have developed deeper flavor, although if there is excess salt present it should be wiped off with clean paper towels before cooking. Discard the aromatics. Bring the rendered duck fat up to a barely noticeable simmer—say around two hundred degrees fahrenheit—and slip in the duck legs making certain the fat comfortably covers each leg. Simmer on the stove or in the oven for two or three hours, or until a clean knife easily passes in and out of a leg. Let cool, wrap or cover tightly, and return whatever vessel is being used to the refrigerator. What’s been created is a sterile environment; any remaining bacteria has been destroyed by the heat, and the thick layer of congealed fat hermetically seals the legs, preventing any new bacteria and oxygen from spoiling the meat. As is, the legs will last six weeks or longer.

Enough casual science though; confit is meant to be eaten. On an appointed evening, open a few bottles of Beaujolais. Dig out the duck legs and set aside. It would be a pity to waste all the lovely duck fat; my preferred use is to scrape it into a medium sized pot and deep fry sliced potatoes for game chips. When dinner guests are assembled, heat a large heavy-bottomed pan, and brown the duck legs skin-side down until crisp. Flip and finish with a ten minute roast in a hot oven. Serve with baguette and a salad of chicories dressed with vinaigrette. A cautionary note: the ease of the final preparation might suggest to the less experienced home cook that some additional stroke is needed. A spiced couscous, or saffron risotto. Resist the urge: the magic of duck confit is in the apparent imbalance between effort and jaw-slackening flavor.