Baked Alaska is a dessert consisting of cake and ice cream encased in a thick layer of meringue and quickly browned in a hot oven. The dish works because of the insulating properties of the meringue. The air bubbles trapped in the whipped egg whites act as a thermal barrier, preventing the heat of the oven from reaching the frozen ice cream. It was reportedly popularized by Chef Charles Ranhofer at Delmonico's in New York in 1867 to celebrate the U.S. purchase of Alaska from Russia. The dessert is often flambéed at the table with brandy for extra spectacle.