Sponge Cake

Huh. Here’s a strange recipe.

Missing a measurement, but we can fix that. Fortunately, the seven egg sponge cake is such a well-known recipe that the proportions aren’t that mysterious.

Still, this one is a bit odd. Ordinarily speaking, the process for making sponge cakes is to beat the sugar with the egg yolks till pale, then beat in wet ingredients, then fold in the stiffly beaten egg whites, and then fold in the flour. Some variations will have you divide the sugar between the yolks and the whites evenly, which helps the whites hold up a bit.

But this recipe takes it to another level by having you make an Italian meringue with the whites. Now, a French meringue is made when you beat sugar into egg whites. The Italian version has you beat a hot, thick sugar syrup into the whites as they’re being beaten, cooking them and creating a meringue that’s much more stable and can be eaten directly.

Egg white beaten with sugar syrup by Amy Stephenson, on Flickr (CC License)

While this means the egg whites in this recipe are getting cooked twice, I really can’t think of any reason why that should hurt them. While egg proteins are sensitive to increases in temperature, they can hold at a temperature for a long period if they need to. (These days, if you go to a fancy restaurant and they serve you a perfectly soft boiled egg with a runny yolk, those eggs are usually spending the night sitting in a water bath held at 149 degrees Fahrenheit.)

So why don’t we use this method all the time? Well, it’s not as simple as it sounds, honestly. It’s at least a two-person job without a stand mixer. Here’s the problem: if the sugar syrup touches the side of the bowl or the beaters, beads of sugar will cool and crystallize on the metal, which will then be beaten into your egg whites, leaving odd crunchy bits in your cake. That’s what happens when you’re making a traditional buttercream frosting, which is made by beating sugar syrup into egg yolks (or whites, for a white buttercream) and then beating butter into the resulting room temperature mixture.

Of course, there’s another ingredient we know that’s made with a sugar syrup (corn syrup and sugar) and egg whites (powdered, in this case): marshmallow Fluff.

From a box sold in River Forest, Illinois.