If you make roast chicken or chicken stock fairly often, it takes little extra effort to have a supply of rendered chicken fat (schmaltz) on hand for use in recipes such as chopped chicken liver and borscht. There’s always surplus fat to be trimmed from whole chickens, especially from the neck, body cavity, and tail areas. I save the bits of fat in the freezer, adding to my cache until I have at least a cup or two. To render fat, defrost it slightly, cut into ½- or 1-inch pieces, and place them in a heavy skillet or saucepan over low heat. Add about ¼ cup water (to prevent the fat from sticking) and cook gently, stirring occasionally, until the fat has liquefied and the solids have shrunk and become crispy brown bits, about 10 to 15 minutes. Let the fat cool slightly before straining it through a finemesh strainer into a storage container with a tight-fitting cover. (In Yiddish the crunchy pieces left behind are called gribenes, and in the old days before cholesterol was declared the enemy they were considered quite a treat.) Store rendered fat in the refrigerator for a month or in the freezer for up to a year. To render duck or goose fat, follow the same procedure.