I think of the whipping method as “European” and I don’t think that’s an inaccurate assessment, since you only tend to come across it when making spongecakes like génoise, joconde, ladyfingers or specialty cakes like rehrücken. I can’t think of any common uses for the whipping method here in the States, except perhaps for flourless chocolate cake. Essentially, the whipping method is how European bakers create very light cake layers in the absence of chemical leaveners.
You need a lot of eggs — plus plenty of sugar, which helps create a thick syrup that keeps the egg foam from collapsing. The neat thing about the whipping method is that it gives lie to the myth that egg foams can only be created with whites. Twaddle. Indeed in most instances where the whipping method is employed you’re whipping either whole eggs or egg yolks plus sugar. Egg whites plus sugar are a rarity in the whipping method universe because, well, then you’d have a meringue, would you not?
But I digress. In general sponges made via the whipping method begin with the egg-sugar foam. Any flavorings (like chocolate) are added next, then the dry ingredients are carefully folded in so as to preserve the bubbles (I said you can make a foam with egg yolks…I didn’t say that foam was stable). Sometimes a meringue is folded in as well to add more volume.
The upside of the whipping method is that it creates sponges that are very light, sweet and eggy-tasting. The down side is that those sponges can be a little dry tasting, at least by New World standards. All this begs the question: why use the whipping method at all when perfectly good chemical leaveners are available? The answer is because egg sponges have a cleaner taste and a lighter texture. The high proportion of egg can also create very plastic sheets of sponge that are perfect for rolling into things like yule logs. And anyway, dry cake is what cake syrup is for!