Seventh Heaven Chocolate Truffle Cake

By AzWench

Ingredients

• Cake:
• 2 1/3 cups cake flour
• 1 1/2 teaspoons baking soda
• 1 teaspoon salt
• 1 ounce unsweetened chocolate
• 1/2 cup unsalted butter, at room temperature
• 2 1/3 cups firmly packed golden brown sugar
• 3 large eggs
• 2 teaspoons vanilla
• 1 cup sour cream
• 1 cup boiling water
• Ganache Frosting:
• 24 ounces bittersweet chocolate (70 percent cacao), finely chopped
• 1/2 cup unsalted butter, at room temperature
• 2 1/2 cups heavy whipping cream
• 2 teaspoons vanilla
• 1/4 cup light corn syrup
• Truffle Filling:
• 8 ounces semisweet chocolate, chopped into small pieces
• 3 ounces unsweetened chocolate, chopped into small pieces
• 1 1/2 cups unsalted butter
• 1/2 cup heavy whipping cream
• 6 large egg yolks
• 2/3 cup powdered sugar
• 1 tablespoon vanilla
• 2 tablespoons Grand Marnier (optional)

Details

Servings 10

Preparation

Step 1

To Make the Cake: Preheat the oven to 350 degrees. Line two 12 X 17-inch rimmed baking pans with silicone mats or parchment paper and coat with nonstick cooking spray. Make sure the parchment paper is wrinkle-free or the cakes will be uneven when baked. Place one baking rack 1/3 from the bottom of the oven and the second 2/3 from the bottom. (If you only have one baking pan, you can bake the cakes separately on the middle rack of the oven, washing pan after baking the first cake and preparing it as you did the first time.)

Sift together the flour, baking soda, and salt in a medium bowl. Coarsely chop the chocolate and melt it in a small metal bowl set over a saucepan with 2 inches of simmering water, or in a microwave. Stir the melted chocolate until smooth and remove it from the heat.

Using an electric mixer fitted with a paddle attachment, beat the butter and sugar in a large bowl on medium-high speed about 2 minutes, until light and creamy. Add the eggs, one at a time, beating on medium speed for 30 seconds after each addition. Add the melted chocolate and vanilla to the batter and beat until incorporated. Add one-third of the flour mixture and beat on medium speed for 20 seconds. Add 1/2 cup of the sour cream and beat for another 20 seconds. Continue alternating additions until all the dry ingredients and sour cream have been added. Add the boiling water and mix thoroughly on medium speed for 30 seconds.

Pour the batter into a large measuring cup. Pour half of the batter into each of the prepared pans. Bake for 7 to 12 minutes, until the cake springs back when touched lightly or a toothpick inserted into the center comes out clean. Monitor the layers carefully for doneness; they may be done at different times. Remove the cake from the oven and cool at least 30 minutes.

To Make the Ganache: Place the chocolate and butter in a medium bowl. Heat the cream in a small saucepan over medium heat until it is very hot and just begins to steam. Pour the hot cream over the chocolate and butter and stir until the mixture is smooth. Add the vanilla and corn syrup; stir until the ganache is smooth and glossy. The ganache will be too soft to frost the cake immediately; it must sit at room temperature about 2 hours to firm up. The ganache can be made the night before the cake is assembled and left, covered, at room temperature. (Do not refrigerate it, or it will become too hard to handle.)

To Make the Truffle Filling: Melt both chocolates, the butter, and the cream in a large bowl set over a saucepan with 2 inches of simmering water. Remove from the heat to cool. Using a mixer fitted with a whisk attachment; whip the egg yolks in another large bowl on high speed about 5 minutes, until thick and light in color. Add the melted chocolate mixture and beat on medium-high speed for 1 minute. Add the powdered sugar, vanilla, and Grand Marnier and mix on medium speed until incorporated.

To Assemble the Cake: Invert the cooled cake onto a flat surface lined with waxed paper. Cut each cake into 3 equal rectangles. You will have 6 rectangles of cake total. Put 1 cake layer on a cake plate, spread the top with a thick layer of truffle filling (about one-fifth of the filling), and cover the filling with another layer of cake. Continue with a layer filling and a layer of cake until all of the cake layers are used, but do not spread filling over the top layer. Cover the cake with plastic wrap and refrigerate about 2 to 3 hours, until firm.

Remove the cake from the refrigerator and frost it with the cooled ganache. Cut the cake with a long serrated knife, dipping it in a tall glass of hot water between each slice. Well wrapped, the cake will keep in the refrigerator for up to 1 week or in the freezer for up to 3 weeks.

Note: A ruler or dental floss can ease the job of cutting this cake into equal parts before frosting. Use the ruler to measure out three equal portions of each cake, measuring from one side of the cake's short end to the other. Stretch unflavored floss from one end of the cake to the other and push down lightly to mark a straight line. Follow the line with your knife to cut the cake into squares.

Planning is essential here, because once the cake is layered with truffle filling it must be refrigerated at least two hours. And don't forget to make the ganache frosting early. It must sit at room temperature for at least two hours to reach the proper consistency for frosting the cake. If you're truly organized, make the whole thing in advance and refrigerate the well-wrapped cake up to three days, or freeze it up to three weeks.