...what are the different types of sponge cakes?

Oh man. I have to stop watching the Great British Baking Show and/or I need to hit the gym.

But it has me trying to learn as I listen, which makes watching it seem suuuuper productive and not a time suck... right? So I was wondering, and this is going to sound ridiculous, but what types of cake are there? I think my main take away from watching several seasons is that a Genoise is made by beating the hell out of egg whites. And the more air in there, the more the oven heat will make those bubbles expand and that's what makes the cake rise. WHOA, I know stuff!!

-----------------(cue charming BGGS intro music)---------------------------------

What kinds of cake are there? Two. There are two kinds.

1. Butter (or "shortened")
butter/margarine/vegetable shortening = dense, moist
think: pound cake, yellow cake, most cakes in the U.S.

2. Sponge (or "foam")
little to no fat + usually larger proportion of (often separated) eggs = light, airy
think: sponge cakes, angel cake, Swiss rolls, tres leches (yes!), madelines, lady fingers

Key notes on sponge: 

-little or no butter, or it won't rise

-might just use whipped eggs/whites, but might also use baking soda or cream of tartar if there IS butter

-maybe don't grease the pan? it might help it climb and rise more.

-great for gluten-free because it's the eggs that give the structure, not the gluten

Basically: whip egg whites with caster sugar, then fold in flour.