The fat used in its preparation can define virtually every kind of cooking. For the Jews of Eastern Europe, schmaltz ruled. Because of the dietary laws, they couldn't use butter with meat or lard at all as a grease for cooking. Schmaltz, the fat from geese (and occasionally chicken) was available and cheap. Inventive Jewish cooks made a virtue of necessity and schmaltz became a way of life. Charlie Klatskin from New Jersey renders the classic gribenes - chicken skin and onions cooked in chicken fat, which he happily smears on bread for a traditional and substantial nosh. Then, combining some of the finest French and Jewish culinary traditions, Ariane Daguin, owner of New York's D'Artagnan restaurant, roasts a whole goose with braised cabbage, flavored with - what else - schmaltz.