From America's Test Kitchen Season 7: Old-Fashioned Chocolate Cake
Over the years, chocolate cakes have become denser, richer, and squatter. Many contemporary cakes are so intense that just a few forkfuls satisfy. These cakes taste great—it’s hard to imagine a bad chocolate cake—but sometimes we’d rather have a real piece of cake, not a fudge-like confection. We wanted an old-style, mile-high chocolate layer cake with a tender, airy, open crumb and a soft, billowy frosting. The mixing method was the key to getting the right texture. After trying a variety of techniques, we turned to ribboning, a popular old-fashioned method used for cakes like genoise (a moist, light sponge cake). Ribboning involves whipping eggs with sugar until they double in volume, then adding the butter, dry ingredients, and milk. The egg foam aerated the cake, giving it both structure and tenderness. To achieve a moist cake with rich chocolate flavor, we once again looked to historical sources, which suggested using buttermilk and making a “pudding” with a mixture of chocolate, water, and sugar. We simply melted unsweetened chocolate and cocoa powder in hot water over a double boiler, then stirred in sugar until it dissolved. Turning to the frosting, we wanted to combine the best elements of classic chocolate frostings: the intense chocolate flavor of a ganache (a mixture of chocolate and cream) and the volume of a meringue or buttercream. The solution turned out to be a simple reversal of the conventional ganache procedure: We poured cold (rather than heated) cream into warm (rather than room-temperature) chocolate, waited for it to cool to room temperature, then whipped until fluffy.
Serves 10 to 12
Do not substitute semisweet chocolate chips for the chopped semisweet chocolate in the frosting—chocolate chips contain less cocoa butter than bar chocolate and will not melt as readily. For best results, don't make the frosting until the cakes are cooled, and use the frosting as soon as it is ready. If the frosting gets too cold and stiff to spread easily, wrap the mixer bowl with a towel soaked in hot water and mix on low speed until the frosting appears creamy and smooth. Refrigerated leftover cake should sit at room temperature before serving until the frosting softens.