Doughnut toppings are a popular way to add flavor and texture to the classic pastry. The two most common doughnut toppings are GLAZE and icing. GLAZE is a thin, sweet coating made from sugar, water, and sometimes other flavorings. Icing is a thicker, sweeter topping made from sugar, butter, and other flavorings. Both GLAZE and icing can be flavored with a variety of ingredients, such as chocolate, vanilla, or fruit.