A sponge cake is a cake which is made with flour, sugar, and eggs, but no shortening. As a result, the cake is distinctly light and fluffy when it is prepared well. These cakes are also very porous, marked with distinctive holes that make them look rather a lot like sponges. In addition to being served on its own, sponge cake is used as the base for many desserts, since it is a very sturdy, durable cake. Its absorbency makes it ideal for desserts that call for cake soaked in syrup or alcohol, since the cake will soak up the flavor without falling apart.
Making this type of cake properly does require some skill. It relies on eggs for its leavening, along with a small amount of baking powder in some recipes. The eggs need to be well beaten to integrate air, and the ingredients have to be carefully mixed to ensure that the air bubbles are not forced out. Sponge cake also has to be carefully cooled, as rapid cooling can cause it to collapse and become very heavy. Bakers sometimes make several attempts before they manage to succeed.
Base sponge cake recipes are very easy to modify with additions of extracts like lemon, almond, chocolate, coconut, orange, and vanilla. The clear, light flavor of the cake allows these flavors to come through without obscuring or overwhelming them. The cakes can also be frosted with light, delicate frostings or jam; Victoria sponge, a classic version, is made by sandwiching jam and whipped cream between layers of cake. The versatility of the sponge makes it very popular with bakers who want flexibility in their finished goods, since it allows them to play around with flavors without the risk of messing up the cake.
There's another unique attribute to sponge cake that makes it popular with bakers. The cake remains flexible as it cools, so bakers can make it in a sheet and then roll it up with ingredients like jam, chocolate spreads, and custard. Numerous rolled cakes use a sponge as the base as a result. Rolled cake is surprisingly forgiving for cooks who are just beginning to experiment, so once a baker masters the art of the sponge generally, he or she can achieve quick gratification with a rolled one.
Culinary historians believe that sponge cake probably emerged around the early 19th century, because this is when it first started appearing in recipe books. The cake quickly became popular since it was so versatile, and the basic principle of a light, fluffy cake spread across much of the Western world, where various regions developed their own versions. The French Genoise and American chiffon cake are two examples of regional derivatives.