A chiffon cake is a type of sponge cake. It is a cake that is made using vegetable oil instead of butter. This gives the cake a foam-like texture. Because there is no butter in the cakes, they are more healthy but have less flavor. Chiffon cakes are usually served by soaking the cake layer in a cake syrup (which is nothing more than 2 parts water to 1 part sugar) to provide it with moisture since it's dry in nature.