For her birthday, my younger sister Julia asked for a chocolate on chocolate cake. Last year I baked her a devil’s food cake. While I searched for a slight variation on the theme, I came upon Dahlia Bakery’s double chocolate cake, perfect for a celebration. This one is topped with a fluffy frosting that uses both bittersweet and milk chocolate. The use of sour cream adds some tang and the frosting has a hint of salt.
Make sure to use room temperature ingredients for both the cake and the frosting. Also, do not refrigerate this frosting before spreading it onto the cake. It’s best to bake the cake, let it cool, and then make the frosting. If you’ve made the frosting and are not ready to use it, simply leave it on the counter at room temperature with a plastic wrap cover.
Recipe Source: The Dahlia Bakery Cookbook
Yields one 9-inch layer cake, serves 12
230 grams (1 1/2 cups) cake flour, + 2 tbsp for the pan
45 grams (1/4 cup + 1 tbsp) cocoa powder, + 2 tbsp for the pan
70 grams (1/4 cup) finely chopped bittersweet chocolate
210 grams (1 cup + 1 tbsp.) granulated sugar, preferably superfine
1/2 tsp. baking powder
1/2 tsp. baking soda
1/2 tsp. kosher salt
230 grams (1 cup) buttermilk, at room temperature
2 tsp. pure vanilla extract
2 eggs, at room temperature
70 grams (1/3 cup) packed brown sugar
200 grams (1 cup) canola oil
230 grams bittersweet chocolate, chopped
115 grams milk chocolate, chopped
230 grams (1 cup/2 sticks) unsalted butter, softened
150 grams (1 cup) powdered sugar, sifted (measure first, then sift)
230 grams (1 cup) sour cream, at room temperature
2 tsp. pure vanilla extract
3/4 tsp. kosher salt
1) Preheat the oven to 350F.
2) Butter a 9-inch round springform pan. Line the bottom with parchment paper. Whisk together 2 tablespoons of flour with 2 tablespoons of cocoa powder. Dust the pan with the mixture, shaking out the excess. Chill the pan in the fridge to set the coating while you make the batter.
3) Melt the chocolate in a heatproof bowl set over a saucepan of simmering water. Remove the bowl from the heat and let the chocolate cool slightly, until it is a bit warmer than room temperature, about 5 minutes. The chocolate must still be warm to the touch when you add it to the batter.
4) Sift the flour, cocoa powder, 1/2 cup of the granulated sugar, baking soda, baking powder, and salt together. Set aside.
5) Combine the buttermilk and vanilla in a small bowl. Set aside.
6) In the bowl of an stand mixer fitted with a whisk, whip the eggs, brown sugar and remaining granulated sugar on medium-high speed until very pale and tripled in volume, 5 to 6 minutes.
7) Reduce the speed to medium and add half of the oil slowly and gradually.
8) Pour the melted chocolate into the bowl of the stand mixer and mix until incorporated.
9) Add the rest of the oil slowly and gradually.
10) Reduce the speed to medium-low and add the buttermilk-vanilla mixture slowly.
11) Use a rubber spatula to fold in the dry ingredients in 3 or 4 additions. Do not overwork the batter.
12) Pour the batter into the prepare pan and bake for 50 to 55 minutes.
13) Transfer the pan from the oven to a wire rack and let cool for 5 to 10 minutes.
14) Unmold the cake and let cool completely. Slice the cake to create two layers.
1) Melt both chocolates in a heatproof bowl set over a saucepan of simmering water. Remove the bowl from the heat and set aside for the chocolate to cool to room temperature.
2) In the bowl of a stand mixer fitted with a paddle attachment, cream the butter and sugar on medium-high speed for 5 minutes. The mixture will be very pale and white.
3) Reduce the speed to medium-low and add the sour cream, beating until incorporated.
4) Add the melted chocolate, vanilla and salt. Turn the mixer to medium-high speed and beat for 1 minute.