Foie gras, literally "fat liver" in French, is the liver of a duck or goose transformed into a rich delicacy through force-feeding.  Traditionally, foie gras meant goose liver but many producers of foie gras turned to duck liver because ducks were easier to raise.

Many associate foie gras with the French the process actually goes back to the ancient Greeks and Egyptians who fed their birds moistened grain or figs.  Prior to the introduction of corn from the New World, the French used barley or millet, and later chestnuts, as feed.

Raw French duck and goose livers, which had been banned in the United States for many years, became available in 2000 and are sold either fresh or frozen.  Moulard is the duck that's most commonly used for foie gras. Starting between 9 and 13 weeks of age, ducks are fed an intensive diet of corn that almost doubles the overall weight by the end of the two to four week feeding period.  The result of this process is a liver weighing 12 to 26 ounces which is 10 times the normal weight.

Duck foie gras is produced in the United States by Bobo Farms and Hudson Valley Foie Gras both in New York and Sonoma Foie Gras in California.  California has however banned the production of Foie Gras effective 2012.