Did you know that a sponge cake or chiffon baked in a sheet pan and then rolled around a filling is called a roulade (for the french), a jelly roll (for the americans), or a swiss roll (for the english). swiss rolls are slightly different from jelly rolls or roulades; the sponge cake layer is thicker so it cannot be rolled as tightly.
sponge cakes are light and airy cakes made without a solid f*t which contain more eggs and less f*t or flour than butter cakes. leavening comes mainly from the air whipped into the eggs, although some american sponge recipes do contain a small amount of baking powder. often times corn starch replaces some of the flour to make a sponge with a more delicate texture, finer crumb and tighter grain.