Chocolate Layer Cake with Chocolate Frosting

Written on February 13, 2020. Posted in Desserts, Recipes.

WHY THIS RECIPE WORKS

Three kinds of chocolate—unsweetened, milk, and cocoa powder—work together to make a moist, rich frosted cake with flavor that reads more “chocolate” than “sweet.” The frosting came together in just a couple of minutes with the help of the food processor. The quick cutting motion of the blade emulsified the ingredients into a smooth frosting that didn’t break into a greasy mess as we frosted the cake. Corn syrup was the go-to ingredient, as it imparted an appealing shine to the finished frosting.

INGREDIENTS

Cake

1 ½ cups (7 1/2 ounces) all-purpose flour
1 teaspoon baking soda
½ teaspoon baking powder
¼ teaspoon salt
1 ¼ cups boiling water
4 ounces unsweetened chocolate, chopped fine
½ cup (1 1/2 ounces) Dutch-processed cocoa powder
1 teaspoon instant espresso powder
10 tablespoons unsalted butter, softened
1 ½ cups packed (10 1/2 ounces) light brown sugar
3 large eggs, room temperature
½ cup sour cream, room temperature
1 teaspoon vanilla extract

Frosting

20 tablespoons (2 1/2 sticks) unsalted butter, softened
1 cup (4 ounces) confectioners' sugar
¾ cup (2 1/4 ounces) Dutch-processed cocoa powder
Pinch salt
¾ cup light corn syrup
1 teaspoon vanilla extract
8 ounces milk chocolate, melted and cooled slightly

KEY EQUIPMENT

BEFORE YOU BEGIN

For an accurate measurement of boiling water, bring a full kettle of water to a boil and then measure out the desired amount. Instant coffee can be substituted for the espresso powder, if desired. We also use this batter recipe as the base for our Candy Corn Cake. This frosting can be made with milk, semisweet, or bittersweet chocolate.

INSTRUCTIONS

FOR THE CAKE: Adjust oven rack to middle position and heat oven to 350 degrees. Grease two 9-inch or three 8-inch round cake pans and line with parchment paper. Whisk flour, baking soda, baking powder, and salt together in bowl. In separate bowl, whisk boiling water, chocolate, cocoa, and espresso powder until smooth.
Using stand mixer fitted with paddle, beat butter and sugar on medium-high speed until pale and fluffy, about 3 minutes. Add eggs, one at a time, and beat until combined. Add sour cream and vanilla and beat until incorporated.
Reduce speed to low and add flour mixture in 3 additions, alternating with chocolate mixture in 2 additions, scraping down bowl as needed. Give batter final stir by hand.
Divide batter evenly between prepared pans and smooth tops with rubber spatula. Bake until toothpick inserted in center comes out clean, 15 to 20 minutes (for 8-inch pans) or 25 to 30 minutes (for 9-inch pans), rotating pans halfway through baking.
Let cakes cool in pans on wire rack for 10 minutes. Remove cakes from pans, discard parchment, and let cool completely on rack, about 2 hours.
FOR THE FROSTING: Process butter, sugar, cocoa, and salt in food processor until smooth, about 30 seconds, scraping down sides of bowl as needed. Add corn syrup and vanilla and process until just combined, 5 to 10 seconds, scraping down sides of bowl as needed. Add chocolate and process until smooth and creamy, 10 to 15 seconds. (Frosting can be held at room temperature for up to 3 hours.)
Using serrated knife, shave domed tops from cakes to make them all level; discard tops. Place 1 cake layer on platter or cake pedestal. Place 4 strips of parchment paper beneath edges of cake to keep platter clean.
Using offset spatula, spread 1 cup frosting (for 9-inch cake) or 3/4 cup frosting (for 8-inch cake) evenly over top of first layer, right to edge of cake. Top with second cake layer, press lightly to adhere, then spread 1 cup frosting (for 9-inch cake) or 3/4 cup frosting (for 8-inch cake) evenly over top. (For 8-inch cake, repeat with third cake layer and 3/4 cup frosting.) Spread remaining frosting evenly around sides of cake. Carefully remove parchment strips before serving.

TO MAKE AHEAD: Baked, cooled cakes can be wrapped in plastic wrap and frozen for up to 1 month. Thaw at room temperature before frosting and stacking. (The frosting comes together quickly, so we recommend making it right before assembling the cake.)