In France, parfait refers to a frozen dessert made from a base of sugar syrup, egg, and cream. A parfait contains enough fat, sugar, alcohol, and to a lesser extent, air, to allow it to be made by stirring infrequently while freezing, making it possible to create in a home kitchen without specialist equipment. The fat, sugar, alcohol or air interferes with the formation of water crystals, which would otherwise give the ice cream an uncomfortable texture in the mouth. The formation of ice crystals is managed in the making of regular ice cream by agitating the ice cream constantly while it freezes or chemically by adding glycerol. Neither should be necessary when making a high-quality parfait. Source: (en.wikipedia.org)