Easy Chocolate Sponge Cake
My wife’s birthday had just passed while we were on vacation in early July and I had been wanting to try a sponge cake again, which I’ve had both great success and total disasters (Google “genoise collapse” and you’ll get the idea). So as soon as we got back, and another week and a half later I was finally ready. So I did some recipe research and wrote the following chocolate sponge cake recipe, based mostly on Julia Child’s version.
I was very happy with the texture and moistness of the cake, which I’m always worried about with sponge. I made a sheet out of the cake and cut some circles in order to make some individual servings, instead of an entire 7″ cake for just the two of us. I layered the cake circles with some homemade crème fraîche and a raspberry pastry cream. I will say that I think some simple syrup brushed on the cake and some raspberry jam instead of pastry cream would have been better, but I think even Marie Antoinette would have had no complaints.
1/2 cup Cake flour
4 Egg Yolks
1/4 Cup Sugar
1 Tspn Instant Coffee
4 Egg Whites
1/4 tspn kosher salt
1/4 Cup Sugar
2 Tspn Vanilla
A chocolate sponge cake is all about the air that you trap in it. The more air you can keep in the batter, the more that air will expand with heat and thus have a nice risen cake free of chemical leaveners. Not that I’m against chemistry, but it’s cool to think that we can make a cake rise without baking powder or soda. Anyway, the air mostly comes from the meringue in this case, which you want to beat to soft peaks. Really… soft peaks. Think of the air as tiny bubbles trapped in the egg, and if the bubble is at its maximum size already (stiff peaks) when you bake, it can only pop. Now with soft peaks, the bubble will still have room to expand before it pops, thus a more risen, airy, lighter cake. Yes!
Preheat your oven to 350º.
Start by preparing whatever pan you’re going to use. I used a half sheet pan and this recipe barely covered it, which worked for what I was doing. It would probably make a good 7″ – 8″ cake. UPDATE: For my sheet pan I was able to just put some parchment down, but if you use a regular cake pan, I would suggest buttering the inside and then dusting with some flour. Anything 9″ or over I would also suggest a parchment circle for the bottom of the pan.
So, get a double boiler going and melt the chocolate, butter and instant coffee together stirring gently to blend. You want the mixture well emulsified, but not super hot. While that is happening, in a stand mixer with whisk attachment or with bowl and beaters, beat the egg yolks and 1/4 cup of sugar together until the yolks hold a ribbon. Once ribboning, incorporate the chocolate mixture, beating it into the yolks.
Clean the whisk attachment or beaters thoroughly and dry them. This is super important, because if any fat at all gets in the egg whites, they will not expand at all. Make an omelet cause there’s no fixing them. Whip the egg whites until they are beginning to foam and then, in a steady stream, add the other 1/4 cup of sugar, the salt and the vanilla extract. Whip until soft peaks.
Using a rubber spatula gently, gently fold the whites into the chocolate mixture. Do it in 3 – 4 additions and make the first one the smallest. Then, sift the flour over the mix and just as gently fold it in. Do this in another 3 – 4 additions. Pour the batter into your prepared pan and bake until set. Baking time will vary depending on the pan. My sheet pan was ready in only 20 minutes or so.
Let it cool, cut, brush with a simple syrup, decorate and eat.