The earliest extant description of what is now often called a cupcake was in 1796, when a recipe mug cake “a light cake to bake in small cups” was written in American Cookery by Amelia Simmons. In the early 19th century, there were two different uses for the term cup cake or cupcake. In previous centuries, before muffin tins were widely available, the cakes were often baked in individual pottery cups, ramekins, or molds and took their name from the cups they were baked in.
The other kind of “cup cake” referred to a cake whose ingredients were measured by volume, using a standard-sized cup, instead of being weighed. A standard cupcake uses the same basic ingredients as standard-sized cakes: butter, sugar, eggs, and flour. Nearly any recipe that is suitable for a layer cake can be used to bake cupcakes. Because their small size is more efficient for heat conduction, cupcakes bake much faster than a normal layered cake. During baking, the volume of the batter initially increases due to the production of carbon dioxide, then decreases upon cooling due to the release of leavening gases. Cupcakes may be topped with frosting or other cake decorations. Elaborately decorated cupcakes may be made for special occasions.
They may be filled with frosting, fruit, or pastry cream. For bakers making a small number of filled cupcakes, this is usually accomplished by using a spoon or knife to scoop a small hole in the top of the cupcake. Another method is to just insert the pastry bag in the middle of the cupcake. In commercial bakeries, the filling may be injected using a syringe.