Chafing dishes found in the ruins of Pompeii prove that this style of cookery is nothing new. Used to warm or cook food, a chafing dish consists of a container (today, usually metal) with a heat source directly beneath it. The heat can be provided by a candle, electricity or solid fuel (such as Sterno). There's often a larger dish that is used as a water basin (like the bottom of a double boiler) into which the dish containing the food is placed. This prevents food from burning.