Technically a soufflé is a cake, however Julia Child defines it as — and I’m paraphrasing — a sauce to which a flavoring has been added, lightened with whipped egg whites and baked in the oven until browned. I prefer that definition because it highlights all the various process steps, each of which are important to a good soufflé.
Soufflées obviously have a reputation for being very finicky things to prepare, especially to bake. The definitive answer on that is that it’s true in some cases, but not in others. To understand exactly why, we’ll need to do a little refresher on the how’s and why’s of egg foams. If you haven’t done so in a while, I suggest you go back and read the posts on egg foams over there on the right.