Icing, often called frosting creamy glaze made of sugar with a liquid, such as water or milk, that is often enriched with ingredients like butter, egg whites, cream cheese, or flavorings. It is used to cover or decorate baked goods, such as cakes or cookies.
Covering cakes with powdered sugar or other materials were introduced in the 17th century. The icing was applied to the cake then hardened in the oven. The earliest attestation of the verb 'to ice' in this sense seems to date from around 1600, and the noun 'icing' from 1683.'Frosting' is first attested in 1750.
The simplest icing is a glacé icing, containing powdered sugar and water. This can be flavored and colored as desired, for example, by using lemon juice in place of the water. More complicated icings can be made by beating fat into powdered sugar, by melting fat and sugar together, by using egg whites, and by adding other ingredients such as glycerin .Some icings can be made from combinations of sugar and cream cheese or sour cream, or by using ground almonds.