For most people, tender, American-style, fat-rich cakes—called butter (or shortened) cakes—are the paradigm of the genre. But foam cakes, equally noteworthy and delicious, are often overlooked, which is a pity given how versatile they are. These get most of their lift and structure from whipped eggs; what they lack in buttery flavor, they make up for with a wonderfully airy texture.
The classic example is angel food cake: white and billowy as a cloud, it has no fat at all. Sponge cake gets fat and a bit of extra heft from the addition of egg yolks; genoise and chiffon cakes have egg yolks as well as a bit of butter or oil. Rarely will you see any of them served unadorned. True to their name, foam cakes are porous and best suited for layering, soaking, and/or saucing—if anything, the addition of a sauce serves to highlight the cake’s simplicity. Try them also in Jelly-Roll Cakes or Petits Fours or see Dressing Up Cakes for your own creative spin.