12-Layer Chocolate Truffle Cake
Tools.
six 8-inch cake pans (I baked the batter in six pans, and then split the cakes for a total of 12 layers, but I understand if you don't have six pans. You can bake the cake in three 8-inch pans, and then "try" splitting those into four thin layers, but I imagine that it would be very difficult to split them evenly. If you only have three pans, a better option might be baking just half your batter at a time, letting the cakes cool, remove them and wrap in plastic, then use the pans again to bake the remaining half of the batter. This rest time might affect the leavening in the batter, and I can't guarantee your second batch of cakes will rise quite as they should, but I am sure this is something that many people do successfully, when they don't have an abundance of pans. And if you don't want to do 12 layers, don't! This cake would be just as delicious with six layers of cake filled with custard.)
large mixing bowl
measuring cups and measuring spoons
medium-sized saucepan
whisk
rubber spatula
icing spatula
adjustable large cake mousse mold (like this one), not totally necessary, but it does greatly help keep the many layers even while stacking
long sharp knife for splitting the cakes
cake lifter, for lifting the split layers of cake (This is absolutely necessary. The layers are extremely thin, and if you try to pick them up with your hands, without the help of a cake lifter, they will undoubtedly break apart) - this is the one I have
large baking sheet
Cake.
2 cups all-purpose flour
1 3/4 cups granulated sugar
3/4 cup unsweetened Dutched cocoa powder (I used Rodelle brand for this cake)
1/2 teaspoon baking powder
1 1/4 teaspoons baking soda
1 teaspoon coarse Kosher salt
4 large eggs, lightly beaten
1 cup whole milk
1 cup sour cream
1 cup vegetable oil
1 tablespoon vanilla
1 tablespoon espresso powder (optional)
Custard.
2 1/2 tablespoons unsweetened Dutched cocoa powder (I used Rodelle brand)
2 tablespoons granulated sugar
2 1/2 tablespoons corn starch
2 cups whole milk
2 large egg yolks (save the whites for another use)
2 tablespoons unsalted butter
1/2 teaspoon vanilla
3 ounces good-quality dark chocolate, chopped (I used Chocolove Dark Chocolate, 55% cacao)
Ganache, Garnish and Truffles.
6 ounces heavy whipping cream
6 ounces good-quality dark chocolate, chopped (I used Chocolove Dark Chocolate, 55% cacao)
2 1/2 cups mini semi-sweet chocolate chips (about 1 pound)
2 tablespoons unsweetened cocoa powder
2 tablespoons powdered sugar
coarse salt
Cake.
Preheat the oven to 350. Prepare six 8-inch cake pans by spraying the bottoms of the pans with non-stick spray. After the cakes are cooled, you'll be splitting the six thin cakes into two layers, for a total of 12 very thin layers of cake.
In a large bowl, sift together the flour, sugar, cocoa powder, baking powder, baking soda and salt. Add the eggs, milk, sour cream, oil, vanilla and espresso powder, and whisk well to combine. Divide the batter evenly between the pans (about 1 cup of batter per pan) - either measure or weigh the batter in the pans to ensure they are all the exact same height when baked.
Bake the cakes on two racks placed in the upper and lower thirds of the oven, for about 20 minutes, until a toothpick comes out clean, and the tops spring back when lightly touched. Place on a wire rack, cover loosely with a clean kitchen towel and let cool completely.
These can be baked one day in advance, wrapped tightly in plastic wrap after cooling. If you like, you can chill the cakes in the refrigerator prior to splitting them, as you may find it easier to handle the thin layers while they're cold.
Custard.
The custard will need to be made at least 6 hours in advance, so it has time to chill.
In a saucepan, whisk together the cocoa powder, sugar and corn starch. Slowly whisk in about 3/4 cup of the milk, whisking until smooth, before whisking in the rest of the milk and the egg yolks. Cook over medium heat, while whisking constantly, until thick enough to coat the back of a spoon, then cook for one additional minute. Remove from the heat and whisk in the butter, vanilla and chocolate until smooth.
Pour into a bowl, cover with plastic wrap resting right against the surface of the custard, and chill for at least 6 hours, or overnight.
Ganache.
The ganache will need to be made no more than one hour before you plan to assemble your cake - it needs to be slightly cooled, but still pourable. Note that after covering my cake in two thin layers of ganache, I had enough ganache left to make 5 truffles. If you want more leftover ganache for extra truffles, use 8 ounces of cream and 8 ounces of chocolate.
In a saucepan, heat the cream over medium heat just until it begins to bubble. Meanwhile, chop the chocolate and place in a bowl. Pour the hot cream over the chocolate, let stand at room temperature for 3 minutes, then stir with a spatula until smooth and thick. Set aside to cool for about an hour before assembling your cake.
Assembly.
If you're using a cake mousse ring, set it on a serving plate or cake board, adjusted to an 8-inch diameter. Carefully remove one of the cooled cakes from the pan, and use a long knife to evenly split the cake into two, very thin layers. Slide a cake lifter between the two layers to lift the top layer up, then place it carefully inside the cake mousse ring, or directly on a serving plate or cake board. Spread the cake with a scant 1/4 cup of the custard. Repeat splitting, stacking and filling the remaining layers of cake with the custard - you should have exactly enough custard to fill all the layers, so don't use more than noted for each layer. Remove the cake mousse ring after stacking the final 12th layer of cake on top. If you didn't use a cake mousse ring, and your layers look uneven, you can carefully trim any uneven places with a sharp knife to make the sides as straight and even as possible.
Pour about 1/2 cup of the ganache on top of the cake, and use an icing spatula to nudge it over the edges. As it drips down, spread it around the sides of the cake. Add more ganache as needed, spreading it around just until the cake is covered with a thin layer of ganache. Chill the cake for 20 minutes to set the first layer of ganache.
Repeat the above step to cover the cake in a second thin layer of ganache - you really don't need a lot, just enough to hold all the layers together and to give the chocolate chips something to stick to. Refrigerate any leftover ganache to let it firm up for your truffles.
Set the cake on a large baking sheet. Before the ganache firms up, press handfuls of the mini chocolate chips around the sides and on top of the cake. Scoop up any that fall and keep pressing them onto the cake until it's covered to your liking.
Refrigerate the cake for several hours (or overnight), to let the custard soak into the cake and the ganache set. Let come to room temperature before serving.
To make the truffles, use a small cookie scoop to scoop balls of the chilled ganache. Roll in the cocoa powder and powdered sugar until coated. Sprinkle with a little coarse salt.
Recipe from Curly Girl Kitchen