I'd heard that tiger-skin Swiss rolls use a lot of eggs, but after some experimentation, I think that's a misconception…it's incredibly egg-intensive! Of course, there's a way to avoid wasting egg whites now: use angel food cake (which doesn't contain egg yolks) with the tiger-skin layer. However, this sacrifices some flavor and texture.
Aside from the egg-intensive nature, traditional tiger-skin Swiss rolls are all advantages. For example, they evoke childhood memories, have a rich egg flavor, a soft and tender texture, are visually appealing, and are high in cholesterol… the last one is debatable, but once you start eating them, it's hard to stop. If you control your portion size, it doesn't matter much.
Don't be fooled by the extra layer compared to other Swiss rolls; making a good tiger-skin Swiss roll isn't difficult. As usual, let's analyze its structure first. It mainly consists of three parts: the tiger-skin layer, the chiffon cake layer, and the filling.
First, let's talk about the filling. There are many choices for the filling in a Swiss roll, such as whipped cream, custard, taro paste, chestnut paste, etc., mainly depending on your preferred flavor. The most common is, of course, whipped cream; it's simple to make and a perfect match for chiffon cake.
Next is the chiffon cake layer. Making it is similar to making a regular chiffon cake in a mold, the only difference being that the egg whites need to be whipped to a lower degree because the Swiss roll doesn't need much expansion (otherwise it wouldn't be able to support the cake). The final batter has a higher fluidity, making it easier to flatten in the baking pan.
Making the tiger-skin layer is much simpler than the chiffon cake layer; its ingredients are only egg yolks, sugar, and starch. Since the egg yolks are the only liquid, and the batter needs to fill a large baking pan (usually 28cm on each side), this is the root cause of the egg yolk waste in the tiger-skin layer. Of course, the leftover egg whites can be used for cooking, or to make angel food cake or meringues.
Why does the tiger-skin layer produce such beautiful patterns? The reason is that it uses pure egg yolks. Egg yolks and egg whites have slightly different compositions. Besides 16% protein, egg yolks contain 33% fat and 50% water. Proteins coagulate upon heating, becoming structural components, while fats soften the texture. As the batter expands in the oven, a small amount of protein coagulates and hardens, while the majority of fat fails to support the surface, resulting in uneven, textured patterns. The higher the baking temperature, the more pronounced the patterns will be.
Overall, making the tiger-skin layer is simple and straightforward; there's no need to worry about deflating or the tiger-skin layer peeling off. However, you need to prevent overbaking, as this will cause it to brown too much and crack when rolled.
Actually, tiger-skin cake rolls can be made without filling. Simply roll up the chiffon cake layer like a plain cake roll, which is perfect for those who don't like cream. However, a small amount of binding material is still needed between the tiger-skin layer and the cake layer. Besides heavy cream, you can choose thick liquids such as jam, salad dressing, condensed milk, or honey.
So, now come and make your own tiger-skin cake roll!
