Buttercream is basically a flavored mixture of butter, sugar and eggs that is used to fill and frost cakes. Whole eggs, yolks or whites may be heated with sugar over simmering water and whipped cold before adding the butter and flavoring, or a sugar syrup cooked to the firm-ball stage can be poured over the eggs, then whipped until cold before the butter and flavoring are added. Buttercream can also be made by combining butter with pastry cream in a 1-to-2 ration or with custard sauce, 1-to-1.
There are many varieties of buttercream used in a pastry kitchen; most buttercreams contain unsalted butter, either egg yolks or egg whites, sugar and flavourings. In most cases, the butter is double the weight of the sugar, incorporating as much air as possible.
A mixture of butter, sugar, and eggs or custard; it is used to garnish cakes and pastries.