Foam cakes are delicate cakes made with little or no fat, such as butter, oil, or shortening, making them lighter and airier than butter cakes.
Most foam cake recipes do not use chemical leaveners such as baking powder or baking soda; instead, they depend on a large amount of whole or separated eggs that are whipped and filled with air bubbles to provide the leavening ingredient that makes the cake rise during baking.
Because foam cakes have a high proportion of eggs to flour, they have a light and spongy texture not found in butter cakes.
The 4 Basic Foam Cakes
The basic foam cakes are Angel food, chiffon, Genoise, and sponge cakes with separated eggs.
- Angel food cake contains no fat and is made with only egg whites and plenty of sugar, providing a moist, tender, extra-sweet cake.
- Chiffon cakes are made with oil and separated eggs; the oil and egg yolk produce a tender crumb and are beaten. Egg whites and a few chemical leaveners produce a light and airy rise.
- Genoise cakes are a classic European cake; the eggs are heated with sugar, beaten until thick, and combined with flour.
- Separated egg cakes are the typical sponge; the egg yolks and egg whites are beaten separately, then gently combined and folded with the flour. Separated egg and genoise cakes may contain butter to provide a moister and more flavorful crumb.
Foam cakes such as Angel Food and Chiffon are moist enough to be served without soaking syrup added.
Classic Genoise and Biscuit Sponge cakes start drier but have a sturdy structure, allowing them to drink and hold lots of moisture. After cooling, the extra moisture is added by sprinkling a soaking syrup onto each layer.
5 Steps to Make a Foam Cake
Preparing the batter for foam cakes eliminates the creaming step to produce air bubbles. Instead, various techniques are used to incorporate air into the eggs.
The recipe may use whole eggs in Genoise cakes, separated eggs in a classic Sponge cake, or egg whites only, such as in an Angel Food cake.
1. Beating Egg Yolks
Egg yolks should be whipped to incorporate air bubbles before being added to the batter. Place room-temperature egg yolks in a small or medium-sized bowl.
The recipe may also state to add sugar and flavoring to the yolks. Beat the egg yolks with an electric hand mixer or by hand using a wire whisk.
With a hand mixer, beat for 3 to 5 minutes on medium-high speed until the egg yolk foam becomes thick and lemon-colored and drops in ribbons when the beater is lifted. This will take a bit longer by hand, depending on how fast and long your arm can endure.
2. Egg Yolk Ribbon Test
Recipes using beaten egg yolks may start to beat until the yolks drop in ribbons.
Lift the beater 2 or 3 inches out of the beaten egg yolks to test for this.
The yolks should be light in color and fall to the surface in thick “ribbons.”
You usually want a three-second ribbon, which means that from the moment the ribbon hits the surface until it disappears and sinks back into the body of the foam, you have been able to count one thousand, two thousand, and three thousand.
3. Heating Whole Eggs
Genoise cakes, whole eggs, and sugar are first heated over a pan of simmering water to dissolve the sugar. This step also increases the mixture, holding more air bubbles.
After warming, beat the egg and sugar mixture using an electric stand mixer for 6 to 7 minutes, or 8 to 10 minutes if using a hand mixer, until it is thick, light in color, and billowy like whipped cream.
Use the ribbon test to determine if the eggs are sufficiently thick.
4. Beating Egg Whites
Egg whites whipped with sugar form meringue, the basis of many foam cakes. The egg whites are usually beaten until stiff but still moist.
Once the egg whites have reached the consistency of stiff peaks, stop beating them. Over-beaten egg whites become lumpy and dry, lose their ability to retain air, and are difficult to blend with other ingredients.
After beating, egg whites begin to break down quickly; therefore, they should be beaten at the end of the recipe, just before they are folded into the batter, to retain as much air as possible.
It is ideal to use a copper bowl to beat egg whites; the copper reacts with the egg whites to produce greater volume, stabilizing the whites so they hold their shape better.
However, not everyone has an expensive copper bowl in their kitchen. Stainless steel bowls work just as well as copper bowls, and adding a small amount of acid should generate the same result as a copper bowl.
Plastic and wood bowls should not be used to beat egg whites, as they are difficult to clean completely of dirt and grease.
Aluminum bowls are also not a good choice as aluminum is corrosive and can impart a grayish color.
Glass bowls may work fine for making meringue, but don’t drop the bowl, as there is always a chance of breakage.
The bowl and beaters you use to beat egg whites must be clean and free of dirt or grease. Even a speck of yolk in the egg whites must be removed, or the fat from the yolk will prevent the egg whites from expanding to a whipped texture.
You can beat the egg whites by hand with a wire whisk; however, using either an electric stand or a hand mixer is far easier. Use room-temperature egg whites and a large bowl.
Beat egg whites starting with an electric mixer on medium-low to medium speed. The whites will look frothy at first, with bubbles forming. At this stage, add cream of tartar or lemon juice. Increase the mixer to medium to medium-high speed.
As you continue beating, soft peaks will begin to form; soft peaks gently droop when the beater is lifted. If the recipe adds sugar, add it at the soft peak stage, one tablespoon at a time or in a slow, steady stream while continuing to beat the egg whites.
Also, add any flavorings at this point. Continue beating the egg white mixture on medium to medium-high speed until stiff peaks form; stiff peaks will look like a soft, glossy meringue and hold their shape when the beater is lifted.
Whipped egg whites are often used to leaven and lighten cake batter; however, they alone cannot support the trapped air in the cake.
Therefore, if no whole eggs, yolks, or unbeaten whites are used in the batter, the cake will rise beautifully in the oven and collapse as soon as the cake begins to cool.
To prevent this collapse, whole eggs or egg yolks are typically added to the batter before the whipped egg whites are folded.
For cakes made with little or no flour, more egg yolks are generally needed to support the cake. The cake will still probably fall when cooled, resulting in a moist and tender cake.
5. Folding Ingredients
Folding is a technique for blending two mixtures. It is used when one of the mixtures is fragile or needs special care to prevent deflating.
Generally, the lighter mixture, such as egg whites or whipped cream, is folded into the heavier mixture, such as chocolate or flour.
Recipe directions may also specify folding ingredients such as flour, chocolate, nuts, and fruits into a batter to avoid over-mixing.
When folding in egg whites or whipped cream, the recipe directions may specify first folding a partial amount to lighten the batter and then folding the remaining egg whites or cream.
Spoon the light mixture on top of the heavier one. Using a balloon-type whisk or large rubber spatula, first cut down through the center of the batter. Use a circular motion with your arm and sweep the whisk or spatula toward you under the batter, across the bottom of the bowl, up the side to the top, and then down through the middle again.
Continue this circular motion, rotating the bowl slightly each time.
Occasionally, run a spatula around the bowl’s inside edge to fully incorporate all ingredients. It may take 2 or 3 complete 360-degree turns of the bowl to fold the ingredients completely; stop when no dry particles are left.
