Confit (pronounced cone-FEE) is a technique for preserving poultry and meats such as duck, goose or pork that involves cooking the meat in its own fat, and then storing it in this fat in a covered container.
Confit is an effective method for preserving meats because the fat seals off the oxygen that bacteria need to reproduce.
The word confit can be used to refer to the technique, or to the meat which has been thus preserved.
For more about how this works, see this article about the six factors that contribute to food spoilage. But suffice to say that bacteria are tiny organisms, which, like us, need food, water and oxygen to survive. So depriving them of one or more of these things kills them, and voilà! Your food is preserved.
Today, it's possible to find restaurants that serve confits made from vegetables or fruits. These aren't true confits in the sense of a meat which is preserved in its own fat, nor indeed are they actually preserved foods. Rather, they're more like jams or chutneys.
Like many classical food preservation techniques, confit belongs to the area of the culinary arts known as garde manger.
To make a classic duck confit, you'd first season duck legs with salt, brown sugar, garlic and fresh herbs such as thyme and other spices. Then, the duck is simmered in duck fat and water for a few hours.
The water will slowly cook off while the fat remains.
Cool to room temperature and then refrigerate the duck in the fat. When you're ready to serve, remove from the fat, and scrape off any excess. But don't discard the fat! You can use it to make confit again, and it's incredible for frying potatoes.
You'll note that duck goose and pork are all foods that come from animals with a relatively large percentage of body fat. And it is the fat that makes confit possible. This is why you don't tend to see confits made from chicken or turkey, since they are comparatively lean and thus lack the requisite fat content to make a proper confit.