This fairly recent American creation was invented by a salesman who sold the recipe to General Mills, which spread the recipe through marketing materials in the 1940s and 1950s.
A classic chiffon cake is kind of a cross between an oil cake and a sponge cake. It includes baking powder and vegetable oil, but the eggs are separated and the whites are beaten to soft peaks before being folded into the batter.
This creates a cake with a tender crumb and rich flavor like an oil cake, but with a lighter texture that’s more like a sponge cake.
Chiffon cakes can be baked in tube pans like angel food cakes or layered with fillings and frostings.