In the Oven: Mile-High Chocolate Cake With Vanilla Buttercream

Six layers of moist and flavorful classic chocolate cake filled with a simple vanilla buttercream, the top layer drenched in a velvety chocolate ganache that just barely drips down the exposed sides… Yes please. Posting date for the Mile-High Chocolate Cake is September 1st!

Yield: One 8-inch, 6-layer cake

For the Classic Chocolate Cake
3/4 cups dark unsweetened cocoa powder (like Valrhona)
1 1/4 cups hot water
2/3 cup sour cream
2 2/3 cups all-purpose flour
2 teaspoons baking powder
1 teaspoon baking soda
1/2 teaspoon salt
6 ounces (1 ½ sticks) unsalted butter, softened
1/2 cup unflavored non-hydrogenated vegetable shortening, at room temperature
1 1/2 cups granulated sugar
1 cup firmly packed dark brown sugar
3 large eggs
1 tablespoon pure vanilla extract

For the Vanilla Buttercream
1 2/3 cups granulated sugar, divided
5 large egg whites
1 pound (4 sticks) unsalted butter, at room temperature, cut into tablespoons
2 teaspoons vanilla bean paste

For the Milk Chocolate Glaze
5 ounces good-quality milk chocolate, coarsely chopped
5 ounces good-quality dark chocolate (60–72%), coarsely chopped
1 ¼ cups heavy cream
2 tablespoons light corn syrup
1 ounce unsalted butter, at room temperature, cut into ½-inch cubes

Make the Classic Chocolate Cake
Preheat the oven to 325 degrees F. Butter three 8-by-2-inch round cake pans, line the bottoms with parchment paper, and butter the parchment. Dust the parchment with flour and knock out the excess flour.

Place the cocoa powder in a medium heatproof bowl. Pour the hot water directly over the cocoa and whisk until combined. Add the sour cream and whisk again until smooth. Set aside to cool.

In another bowl, sift the flour, baking powder, baking soda, and salt and set aside.

In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and shortening on medium speed about 5 minutes, until the mixture appears to ribbon throughout the bowl. Add the sugars and beat until light and fluffy, about 5 minutes more. Add the eggs, one at a time, beating well after each addition, then add the vanilla and beat until incorporated. Scrape down the sides and bottom of the bowl and beat again for 30 seconds.

Add the flour mixture in three parts, alternating with the cocoa mixture, beginning and ending with the flour mixture.

Divide the batter among the prepared pans (about 2 3/4 cup of batter for each) and smooth the tops with an offset spatula. Bake the cakes for 35 to 40 minutes, rotating the pans halfway through the baking time, until a toothpick inserted in the center of the cakes comes out clean. Transfer the pans to wire racks and let cool for 20 minutes. Turn the cakes out onto the racks and let them cool completely. Remove the parchment.

Wrap each cake layer in plastic and place in the freezer while you make the buttercream (this makes them easier to slice in half horizontally later).

Make the Vanilla Buttercream
In a medium, heavy-bottomed saucepan, combine 1 1/3 cups sugar with 1/3 cup of water (be careful not to splash the sides of the pan). Stir gently and cook over medium heat until the sugar is dissolved. Clip a candy thermometer to the side of the pan, making sure the bulb of the thermometer is immersed in the syrup. Stop stirring and increase the heat. Boil the mixture until it reaches the soft ball stage (238 to 240 degrees F), about 5 minutes.

Meanwhile, place the egg whites and the remaining 1/3 cup of sugar in the bowl of a standing mixer fitted with the whisk attachment. Beat on medium speed until very soft peaks form (the mixture will be slightly opaque).

Decrease the mixer speed to low and slowly pour the hot syrup down the side of the bowl into the egg white mixture in a slow steady stream, then increase the mixer speed to high and beat until stiff peaks form. Let the meringue cool in the bowl until the mixture is lukewarm (about 100 degrees F), 10 to 25 minutes.

Turn the mixer speed to medium and gradually add the butter, 2 to 3 tablespoons at a time, beating each addition until it is entirely incorporated before adding more. Continue beating until the buttercream is smooth, light, and fluffy. Add the vanilla bean paste and beat again for 15 seconds to incorporate. (If the buttercream looks broken or curdled, place the mixer bowl over a pot of simmering water on medium heat and whisk with a large whisk for 5 to 10 seconds to warm the mixture slightly. Then remove from the heat and whisk vigorously or attach the bowl to the stand mixer and beat mixture again on medium speed. Repeat warming and beating the buttercream as many times as needed until buttercream is smooth and no longer curdled.)

Assemble the cake
Remove the layers from the freezer and, using a serrated knife, cut each cake in half horizontally, forming six layers in total. (If necessary, trim any domed tops to form even layers.) Place one cake layer on a platter. Drop tablespoonfuls of buttercream (about 3/4 cup in total) over the top of the cake layer and spread evenly to the edges with an offset spatula. Top with a second cake layer and then another 3/4 cup buttercream. Repeat until the sixth layer is stacked–do NOT spread buttercream on the top cake layer. Chill the cake in the refrigerator for at least 1 hour.

Make the Milk Chocolate Glaze
Place the chopped chocolate in a large heatproof bowl and set aside.
In a small saucepan over medium heat, combine the heavy cream and corn syrup and bring just to a boil. Remove from the heat and pour over the chocolate. Let sit for 2 minutes, then slowly blend the chocolate and cream together, whisking from the center, until the chocolate is completely melted and the mixture is smooth. Whisk for another 2 to 3 minutes to release excess heat from the mixture. Add the butter and whisk again until the butter is completely melted and incorporated. Chill the glaze for 30 to 45 minutes, until slightly thickened (it should drip thickly when poured slowly from the spoon).

Spoon teaspoonfuls of glaze up to 2 inches apart around the top edge of the cake, allowing glaze to drip down the sides of the cake. Spoon the remaining glaze over the top center of the cake and smooth with an offset spatula, covering the top completely. Chill the cake until the glaze sets, at least 1 hour.

This cake tastes best when eaten within 24 hours. Refrigerate any leftover cake, tented in foil, for up to 3 days. Let the cake come to room temperature before serving.

Excerpted from Baked Elements: Our 10 Favorite Ingredients by Matt Lewis and Renato Poliafito. Copyright © 2012 by Matt Lewis and Renato Poliafito. Excerpted by permission of Stewart, Tabori & Chang, an imprint of Abrams. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.