In Italy and France, a sponge cake is called genoise; in genoise, whole eggs are beaten with sugar until they’re thick and ribbony, and then flour (and sometimes butter) is added and the batter is baked; the result is wonderful baked in a round cake pan and simply frosted, but genoise is also pliable enough to be baked in a jelly-roll pan and rolled up into a roulade.
Genoise lacks much assertive flavor of its own, but it is often used to construct layered or rolled cakes when a lighter texture than a butter cake is desired.
To add flavor and moisture, genoise cake layers are always moistened with a flavored syrup, and they are often sliced into thin horizontal layers and stacked with rich fillings such as buttercream.
These layer cakes, common in the coffeehouses of Europe, are called “European-style to distinguish them from American-style butter layer cakes, which generally have fewer, thicker layers.
