Flourless sponge cake recipe...
 

I used to have a recipe for a flourless sponge cake (I'm sure
of this) that used a fair few egg yolks that were whisked for
(what seemed like) hours until the mixture - also consisting
of caster sugar - doubled in size. For the life of me, I can't
remember how the recipe went - how many eggs (8, I think),
how much caster sugar (4 oz probably) - and I'd greatly
appreciate it if someone could enlighten me. I'm in a, er,
baking mood. ;-)