*caul fat is a weblike membrane of fatty material that encases the organs of some animals, including pigs, sheep, and cows. when wrapped around meat or fish, it adds flavor, moisture, and fat, and basically melts into the meat or fish as it cooks. some butchers and specialty markets carry caul fat, but you may need to ask your butcher or supermarket meat counter to order it. if you can't find caul fat, try wrapping the halibut in thin strips of bacon.