Chocolate-Chocolate Birthday Cake
This is the birthday cake I’ve made for my son since he was about 11. After boxed cakes, ice-cream cakes, a cake in a Darth Vader mold (that year, the party’s theme was “May the Fours Be With You), this cake hit the spot and remains a favorite. It’s a double-layer devil’s-food cake made with cocoa and bittersweet chocolate, the same pair that makes the frosting so luscious. You can make the layers ahead of time, wrap them and freeze them for up to a month. As for the frosting, it’s best spread between the layers and over the cake when it’s just made. Once assembled, the cake can be refrigerated overnight. It cuts most easily when it’s cold but tastes best when it’s at room temperature, which is about what it will be once the candles are blown out and the slices put on plates. Ice cream alongside is unnecessary but nice. Hey, it’s a birthday!
- Serves: 12 persons
- 2sticks (226 grams) unsalted butter, at room temperature (plus more for the pan)
- ⅔cup (56 grams) unsweetened cocoa powder (plus more for the pan)
- 2cups (272 grams) all-purpose flour
- 1 ½teaspoons baking powder
- ½teaspoon baking soda
- ½teaspoon fine sea salt
- 1 ¼cups (250 grams) sugar
- 4large eggs, at room temperature
- 2teaspoons pure vanilla extract
- 1cup (240 ml.) buttermilk, well shaken
- 4ounces (113 grams) bittersweet chocolate, melted and cooled
- 3 ⅓cups (405 grams) confectioners’ sugar
- 4 ½tablespoons unsweetened cocoa powder
- ½teaspoon fine sea salt
- 3sticks (339 grams) unsalted butter, at room temperature
- 6ounces (170 grams) bittersweet chocolate, melted and cooled
- 4 ½tablespoons buttermilk
- Small decorations to scatter over the cake, optional
Step 1Center a rack in the oven, and preheat it to 350. Butter the interiors of two 9-inch round cake pans, dust with a little cocoa powder and tap out the excess. Sift together the flour, cocoa, baking powder, baking soda and salt.
Step 2Working with an electric mixer (use the paddle, if you have one), beat the butter and sugar together on medium speed for 3 minutes, until light and fluffy. Add the eggs one by one, and beat for a minute after each goes in; beat in the vanilla. Reduce the speed to low, and add the dry ingredients in 3 additions and the buttermilk in 2 (start and finish with the dry, and don’t worry if the buttermilk makes the batter look slightly curdled). Mix in the melted chocolate. Divide the batter evenly between the pans.
Step 3Bake for 24 to 28 minutes, until a tester poked into the center of the cakes comes out clean. Transfer to racks, let rest 5 minutes and then run a blunt knife around the edges of the pans. Unmold the cakes onto the racks, and cool to room temperature.
Step 4Make the frosting: Sift together the confectioners’ sugar and cocoa powder. Using an electric mixer (with the paddle, if available), beat the sugar, cocoa, salt and butter on high speed until fluffy. On low speed, add the chocolate. When it’s almost incorporated, beat in the buttermilk. It’s best to use the frosting immediately.
Step 5If necessary, just before you’re ready to frost the cakes, slice a sliver off the top of each layer to create a flat surface. To assemble, place one cake layer, top up, on a serving platter, and cover with frosting. Top with the second layer, top down, jiggling it into the frosting to hold it in place. Frost the top and sides of the cake — go sleek or swirly. If you’re using decorations, scatter them over the cake. Chill for at least 1 hour (or for up to 1 day); bring to room temperature before serving.