Core Ingredients
Using the right ingredients makes a big difference in foam cake recipes. Here’s a sampler of those often called for in recipes.
Eggs
Whipped eggs or egg whites give foam cakes their light texture and height. Our recipes generally call for large eggs. There’s no difference in flavor between white and brown eggs, so use either in your cakes. If your refrigerator has an egg tray on the door—don’t use it. Eggs should be stored on the shelf, where the temperature is below 40 degrees. The average door temperature in our test kitchen refrigerators is closer to 45 degrees.
Cake Flour
Cake flour has a low protein level (6 to 8 percent) and delivers delicate, fine-crumbed cakes and light, airy biscuits. It’s the right flour for light foam cakes like angel food cake, chiffon cake, and sponge cake. You can also approximate cake flour by mixing cornstarch with all-purpose flour. For each cup of cake flour, use 7/8 cup all-purpose flour mixed with 2 tablespoons cornstarch.
Cream of Tartar
Recipes that require stiffly beaten egg whites often call for potassium acid tartrate, better known as cream of tartar. When egg whites are whipped, the protein strands within begin to unwind and form a network that holds water and air bubbles in place. But egg whites contain sulfur atoms, which form strong bonds that can over-strengthen this network. Acidic cream of tartar slows the formation of the sulfur bonds, preserving the stability of the network so that air and water stay put. If you don’t have cream of tartar, substituting ¼ teaspoon lemon juice or white vinegar per egg white works almost as well.
Vanilla Extract
We use pure vanilla extract in the test kitchen. That said, we have found that you can’t really taste the difference between pure and imitation extracts in baked goods like cakes and cookies. That’s because the amount used is so small and much of the flavor of the extract bakes off in the oven.
Granulated Sugar
Foam cakes' ingredient lists are usually very short. Sugar is an important ingredient for both texture (it's a stabilizer) and flavor (for sweetness). In some recipes, we make our own superfine sugar by blitzing granulated sugar in a food processor, since storebought superfine sugar has a tendency to clump.
