The primary advantage is the one I mentioned: tenderness. A layer cake made via the two-stage method simply melts in the mouth. The trade-off that’s made in the interest of that tenderness is height, and to some extent, lightness. Less activated gluten may mean a rich, fall-apart mouthfeel, but it also means the cake has less structure. If you imagine gluten networks as the girders that hold the building that is a cake layer up, fewer of them mean fewer load-bearing members. And oh my brothers and sisters, do cakes ever carry a heavy load. There’s all that butter, for one thing, to say nothing of the egg yolks, which are plenty fatty all by themselves. Pile on a small mountain of sugar that’s over two-thirds the weight of the flour, and you can practically hear the rivets pop.
Thus, most layer cake recipes call for the standard creaming method. Not only does it create more activated gluten, the creaming of the butter and flour compound the rising action of the baking powder, giving the batter a much stronger lift. The result is a layer that’s lighter and sturdier than the two-stage method, but of course tougher. Are two-stage cakes “dense”? Not in my estimation, but then I’ve always been attracted to slightly squatter layers. One look at them, even when they’re stacked and iced, says “home made cake”. And we know that even at kids’ birthday parties, there’s precious little of that around anymore.
Even some of the best cake bakeries fall prey to the notion that taller is better. They may not be mixing batter the way the big-time cake-carvers do, with as little fat and and sugar as they can get away with — blown up into 3-inch styrofoam-like blocks — but for a variety of reasons as diverse as durability, profit margin and customer expectations, are often not too far removed. Nope, when it comes to real layer cake, there’s simply no substitute for making your own.