What describes "fondant" in dessert making?

Fondant in dessert making refers to a soft, pliable icing primarily composed of sugar and water. This characteristic allows fondant to be rolled out and draped over cakes, creating a smooth and elegant finish that can be shaped and molded into various designs. Its sweet taste and malleable texture make it a popular choice for professional cake decorators and confectioners.

Other types of icings and pastries, like those mentioned in the other choices, do not capture the unique properties of fondant. For example, a dry icing made of egg whites is meringue-based and lacks the pliability and moisture that fondant possesses. Likewise, a pastry dough is used as a base for baked goods rather than a dessert coating, and a custard filling refers to a creamy mixture typically used within pastries or desserts, rather than an outer layer like fondant. Thus, option B accurately conveys the essential nature of fondant in the context of dessert making.