The salt used in modern duck confit not only gives flavor, but also helps the meat retain moisture. As we’ve learned, sprinkling food with salt draws water from inside the meat to the surface. Eventually the water flows back into the meat, carrying the salt with it. An overnight salt cure is the perfect amount of time to properly season the duck legs.
For the fat, there’s only one kind we recommend cooking the duck in: its own. It’s important to use enough fat to cover the legs in the cooking vessel.
The oven makes it easy to maintain a consistent moderately low temperature with zero hot spots. Cooking the legs for 3 hours at 300 degrees yields the perfect texture. We use a Dutch oven, which fits the legs in a single layer and allows headspace above the fat; a baking dish full of hot fat seems too risky to us.
For vegetables, we choose extra-virgin olive oil. Unlike meat, vegetables don’t have to be fully submerged in the fat, and in fact, the bits that remain above the fat turn irresistibly caramelized.