Begin by making the pastry cream. It will be a major ingredient in the vanilla buttercream that will create a very creamy, rich, buttercream, much like French buttercream. The pastry cream can be made up to 2 days in advance.
In a saucepan, bring milk and salt to a simmer over medium heat.
In the meantime, combine the sugar, corn starch, cream and egg yolks in a large bowl and whisk together for a few minutes until thick and pale yellow.
Slowly, pour the hot milk in the egg mixture one ladle full at a time while whisking.
Pour the mixture back into the saucepan and cook over low heat, whisking constantly until thickened.
Remove from heat and add vanilla extract. Whisk well.
Place the pastry cream into a bowl and cover with plastic wrap.
Refrigerate until cold or if using the same day, set aside until it is room temperature, the same temperature that the softened butter is at.
Next, make the chocolate ganache.
Heat the cream in a small sauce pan until it comes to a boil.
Pour hot cream over chopped chocolate and allow to sit for about a minute to soften the chocolate.
Stir the mixture with a small whisk or a spatula until all of the chocolate melts and the chocolate becomes smooth and shiny.
If there are still some bits of chocolate that have not completely melted (this is common in the winter when the temperature is cool inside the house) pop it in the microwave for no longer than 5 second intervals at a time. You may also continue to melt it over a double boiler. Be careful not to burn the chocolate!! There’s nothing that can fix burned chocolate.
Whisk in the vegetable oil and set aside.
If the pastry cream is very cold, either microwave it at 10 second intervals until it reaches room temperature, or place it in a warm water bath. This can be done by placing the bowl with the pastry cream in a larger bowl filled with warm water.
It is crucial that the pastry cream and the butter at the same temperature in order for the buttercream to be ultra smooth.
Also, as the pastry cream sits after it is made it thickens even more. Beat it in a tabletop mixer until smooth or by hand. If necessary, add 1-2 tablespoons of heavy whipping cream and beat until smooth.
Place the butter, salt, vanilla extract, and confectioners sugar in the bowl of a tabletop mixer. Beat until smooth and fluffy.
Add the pastry cream to the butter mixture in 2-3 batches. Beat until, thick, creamy, and very smooth. About 3-5 minutes.
Place 1 layer of chocolate cake on a cake stand.
Spread about 2 tablespoons of ganache onto the cake.
Pipe a layer of vanilla buttercream over the ganache.
Repeat this process once more and place the last chocolate cake layer over the buttercream.
Ice the cake with a thin layer of vanilla buttercream to create a crumb coat. This may look dirty, but don’t worry. All of the crumbs will become sealed into this buttercream layer and will keep the final buttercream clean and crumb free.
Place the cake in the freezer until the buttercream sets. About 20 minutes.
Frost the cake with the remaining buttercream leaving about 1 cup on the side for decoration.
Place the cake in the freezer for another 20 minutes or until the frosting sets completely.
Melt the chocolate ganache either in the microwave (10 second intervals to prevent burning) or over a double boiler. The chocolate ganache is at the right consistency when it is very thin and flows freely when poured from a spoon.
Pour the thinned ganache over the top of the cake allowing it to drip down the sides for a decorative design.
Allow the ganache to set either in the refrigerator or freezer.
Pipe rosettes on top and garnish with fresh fruit if desired.
Allow the cake to set at least 1 hour before slicing.
This cake freezes very well. Just make sure to store it in freezer safe containers. Pre slicing it helps.
- Makes 1 three layer 8 inch round cake:
- 1 recipe Chocolate Cake Layers
- For the Chocolate Ganache:
- 6 ounces semi sweet chocolate, coarsely chopped
- 3/4 cup heavy whipping cream
- 2 tablespoons vegetable oil (flavorless)
- For the Pastry Cream:
- 2 cups whole milk
- 4 tablespoons corn starch
- 3/4 cup sugar
- pinch of salt
- 4 large egg yolks, at room temperature
- 1/4 cup heavy whipping cream
- 1 and 1/2 teaspoons pure vanilla extract
- 1 pound unsalted butter, soft and at room temperature
- 1/4 teaspoon salt
- 2 teaspoons pure vanilla extract
- 1 cup confectioners sugar (powdered sugar)