OK, I decided.
Chocolate génoise is the foundation upon which a great Black Forest cake is built, and is good for a number of other things besides. Like a classic génoise it’s rather dry, but then it’s whole reason for being is to be soaked liberally with syrup.
2 ounces (4 tablespoons) unsalted butter
3.5 ounces (3/4 cup) cake flour
0.75 ounces (1/4 cup) Dutch-process cocoa
1/2 teaspoon salt
6 eggs, room temperature
5.25 ounces (3/4 cup) sugar
1 teaspoon vanilla extract
Preheat your oven to 375°. Melt the butter in a small saucepan and allow it to cool. Meanwhile, line a 9-inch springform pan with parchment paper. Next, sift together the flour, cocoa powder and salt into a large bowl.
Whisk the eggs, sugar and vanilla together in the bowl of a stand mixer (you’re not actually using the mixer here ) then set the bowl over a pan of gently simmering water. Heat the mixture until it’s just warm, about 115 degrees Fahrenheit. When he egg mixture is warm, place it in the mixer, attach the whip, and whip it on medium-high until it is tripled in volume, about 6-8 minutes.
Turn off the mixer, pour off about 1 cup of the mixture into the melted butter and stir it together. This lightens the butter so it will incorporate a bit more easily in the last step. Pour the mixture back into the mixer bowl, sprinkle on the sifted flour mixture, and using your largest spatula, fold the whole mixture together.
Gently scrape the mixture into the prepared pan and back 35-40 minutes until the cake is just firm. Transfer it to a rack and let it cool for about 5 minutes, then turn it out onto a rack to cool, upside down.