Cocoa-Buttermilk Birthday Cake
FOR THE CAKE:
2 cups all-purpose flour
1/2 cup unsweetened cocoa powder
1/2 teaspoon baking powder
1/2 teaspoon baking soda
1/2 teaspoon salt
2 sticks (8 ounces) unsalted butter, at room temperature
1 1/2 cups sugar
2 large eggs
2 large egg yolks
1 teaspoon pure vanilla extract
1 cup buttermilk
4 ounces bittersweet chocolate, melted and cooled (optional)
FOR THE CHOCOLATE MALT BUTTERCREAM: (not the frosting pictured)
6 ounces bittersweet chocolate, coarsely chopped
1/3 cup (packed) light brown sugar
1/4 cup malted milk powder
1 tablespoon unsweetened cocoa powder
1/4 cup boiling water
2 sticks (8 ounces) unsalted butter, at room temperature
Pinch of salt
3/4 teaspoon pure vanilla extract
2 1/4 cups confectioners’ sugar, sifted
GETTING READY TO BAKE:
Center a rack in the oven and preheat the oven to 350 degrees F. Butter two 9-x-2-inch round cake pans, dust the insides with flour, tap out the excess and line the bottoms with rounds of parchment or wax paper. Put the pans on a baking sheet.
TO MAKE THE CAKE:
Whisk together the flour, cocoa, baking powder, baking soda and salt.
Working with a stand mixer, preferably fitted with a paddle attachment, or with a hand mixer in a large bowl, beat the butter on medium speed until soft and creamy. Add the sugar and beat for about 2 minutes, until it is thoroughly blended into the butter. Add the eggs one at a time, then the yolks one by one, beating for 1 minute after each addition and scraping down the sides and bottom of the bowl as needed. Beat in the vanilla. Reduce the mixer speed to low and add the dry ingredients alternately with the buttermilk; add the dry ingredients in 3 portions and the buttermilk in 2 (begin and end with the dry ingredients); mix only until each new batch is blended into the batter. Scrape down the bowl and, if you want, add the melted chocolate, folding it in with a rubber spatula. Divide the batter between the cake pans.
Bake for 26 to 30 minutes, or until the cakes feel springy to the touch and start to pull away from the sides of the pans. Transfer the cakes to racks and cool for about 5 minutes, then run a knife around the sides of the cakes, unmold them and peel off the paper liners. Invert and cool to room temperature right side up. (Once the layers are cooled, they can be wrapped airtight and left at room temperature overnight or kept frozen for up to 2 months.)
TO MAKE THE BUTTERCREAM:
Melt the chocolate with half the brown sugar in a heatproof bowl set over a saucepan of simmering water. Remove from the heat.
Whisk the malt powder and cocoa together in a small bowl, pour over 3 tablespoons of the boiling water and whisk until smooth. Whisking the melted chocolate gently, gradually pour in the hot malt-cocoa mixture and stir to blend–it should be dark, smooth and glossy; set aside.
Working with a stand mixer, preferably fitted with the paddle attachment, or with a hand mixer in a large bowl, beat the butter on medium speed until soft and fluffy, about 2 minutes. Add the remaining brown sugar and beat for 2 to 3 minutes more, until well blended. Beat in the salt and vanilla extract, then reduce the mixer speed to low. Scrape in the chocolate mixture and mix until smooth. Still working on low speed, gradually add the confectioners’ sugar. When all the sugar is in, increase the mixer speed to medium and beat for a couple minutes. Lower the speed and add the remaining tablespoons of boiling water, then increase the speed and give the frosting another quick spin. It will be light and should be thick enough to use immediately. If it doesn’t hold its shape, beat in just a bit more.
TO ASSEMBLE THE CAKE:
Place one layer top side up on a cardboard round or a cake plate protected by strips of wax or parchment paper. Frost the top of the layer, then cover with the second layer, top side down. Frost the sides and top of the cake, either smoothing the buttercream for sleek look or using a spatula, knife or spoon to swirl it for a more exuberant look.
Refrigerate the cake for at least 1 hour (or up to 1 day, if that’s more convenient) to set the frosting, then bring it to room temperature before serving.
Whipped Chocolate Cream Cheese Frosting (frosting pictured here)
8 ounces cream cheese, at room temperature
6 tablespoons butter, at room temperature
4 heaping tablespoons cocoa powder
2 1/2 cups powdered sugar (about)
1-2 tablespoons heavy cream
Cream the cream cheese and butter until fully incorporated and smooth. Add the cocoa powder, mix to combine. Add the powdered sugar until desired sweetness and consistency is reached. Add 1 tablespoon heavy cream, whip until light. (I added a 2nd tablespoon of heavy cream to make the frosting really light.) Frost cooled cupcakes. Yields enough to lightly frost 24 cupcakes.
The pastry cream I used, below. I added 1 tablespoon frangelico and 1 tablespoon very strong espresso to this pastry cream.
2 cups whole milk
6 large egg yolks
1/2 cups sugar
1/3 cup cornstarch, sifted
2 teaspoons Grand Marnier Liquor
3 1/2 tablespoons unsalted butter, cut into bits at room temperature
Bring the milk to a boil in a small saucepan.
Meanwhile, in a medium heavy-bottomed saucepan, whisk the egg yolks together with the sugar and cornstarch until thick and well blended. Still whisking, drizzle in about 1/4 cup of the hot milk– this will temper, or warm, the yolks so they won’t curdle. Whisking all the while, slowly pour in the remainder of the milk. Put the pan over medium heat and, whisking vigorously, constantly and thoroughly (making sure to get the edges of the pot), bring the mixture to a boil. Keep at a boil, still whisking, for 1 to 2 minutes, then remove the pan from the heat.
Whisk in the Grand Marnier. Let sit for 5 minutes, then whisk in the bits of butter, stirring until they are full incorporated and the pastry cream is smooth and silky. Scrape the cream into a bowl. You can press a piece of plastic wrap against the surface of the cream to create an airtight seal and refrigerate the pastry cream until cold or, if you want to cool it quickly–as I always do–put the bowl into a larger bowl filled with ice cubes and cold water, and stir the pastry cream occasionally until it is thoroughly chilled, about 20 minutes.