Butter cakes are traditionally made using a creaming method, in which the butter and sugar are first beaten until fluffy to incorporate air into the butter. Eggs are then added gradually, creating an emulsion, followed by alternating portions of wet and dry ingredients. Butter cakes are typically rich and moist when stored at room temperature, but they tend to stiffen, dry out, and lose flavor when refrigerated, making them unsuitable for filling or frosting in advance with ingredients that must be refrigerated, such as cream cheese frosting and pastry cream.