Fine-Crumb European Sponge Cake

This basic biscuit cake batter is used to make both ladyfingers and layer cakes. It has a very fine crumb and is excellent for making a cake that will be cut into very thin layers—a 1-inch-thick cake can be sliced into 4 layers with a little practice!

There are two ways you can make thin layer cakes: You can slice a layer crosswise using a serrated knife—which can be awkward, especially if