6ouncessemi-sweet baking chocolate or chocolate chipsmelted
Instructions
Ganache
In a medium microwave-safe bowl, add the chocolate chips and heavy cream. Microwave for 30 seconds and stir. Repeat microwaving in 30-second intervals and stirring after each interval until the ganache is smooth and completely melted. Place in the fridge for 2-3 hours to chill until the ganache firms up and is no longer a pourable consistency.
Cake
Preheat oven to 350 degrees F. Grease two 9-inch round cake pans with nonstick cooking spray. Place 9-inch parchment paper rounds in the bottom of each pan and spray with nonstick cooking spray.
In a medium bowl, add the butter, oil, and cocoa powder. Whisk until smooth.
Next, add the buttermilk, sour cream, vanilla extract, and beaten eggs to the bowl. Whisk until the eggs and sour cream are thoroughly combined and the batter is smooth.
In a large bowl, add the cake flour, sugar, baking soda, baking powder, and salt. Whisk until all of the dry ingredients are combined.
Pour the wet cocoa mixture into the bowl of dry ingredients. Whisk until everything is combined. Try to whisk out most of the lumps.
Place in the preheated oven and bake for 25 to 30 minutes or until they're done. Place a toothpick in the center of the cake and if it comes out clean or with moist crumbs it's done.
Let the cake cool in the pan for about 15 minutes and then turn onto a cooling rack to finish cooling. Let the cakes cool upside down if they're really domed to help flatten them. The top layer may peel off as you flip it back over though.
Buttercream
In a double boiler, add the egg whites and granulated sugar. Place over medium/low heat and let the water in the bottom pan simmer while the egg whites reach 160 degrees F. Stir the mixture until the sugar is completely dissolved.
Once the egg whites hit 160 degrees F using a candy thermometer, pour the egg whites into a stand mixer bowl. Using a whisk attachment, whip on medium until the mixture cools to room temperature. Turn the mixer up to high and continue whipping until a meringue forms and has stiff peaks. You can test to see if it's at the stiff peak stage by turning the whisk upside down. If the meringue peak stands straight up, you've reached the stiff peak stage. If it slumps over, you need to whip it a little longer with the whisk attachment.
Switch the whisk attachment out for the paddle attachment. Add the shortening and butter all at once. Beat until it all comes together in a smooth, creamy frosting. It will thicken up at this point. If the mixture looks like it curdled, keep mixing. It will come back together.
Add the vanilla, 1 cup of the cooled milk chocolate ganache, and the 6 ounces of cooled, melted semi-sweet chocolate. Mix until combined. Scrape down the sides of the bowl. Continue to beat the frosting until any remaining bits are incorporated. The frosting should be thick and creamy. If it looks separated, keep mixing. If it appears to be too runny, place the bowl of frosting in the fridge to chill for about 20 minutes so the butter can firm up some. Once chilled, mix again with the paddle attachment until the frost thickens up.
Add about 1 cup of the frosting to a disposable piping bag fitted with the Wilton 1M piping tip.
Assembling the Cake
Using a cake knife or a cake level, cut the domes off both of the cakes. Make sure the cakes are about the same thickness.
Place the first cake layer cut side down on a cake plate or cake board.
Create a dam with the buttercream by piping the chocolate swiss meringue buttercream around the edge of the cake.
Scoop the remaining chilled ganache into the center of the cake and spread out evenly with an angled spatula all the way to the buttercream.
Add the second cake cut side down on top of the ganache. Gently press down so it's firmly sitting on top of the ganache and buttercream dam but don't press hard enough that all of the buttercream is pushed out. Use an angled spatula to smooth out any of the buttercream that hangs out the sides of the cake.
Scoop a pile of chocolate buttercream on top of the cake and begin making a smooth level top and work the extra frosting down the sides. Don't pick up your angled spatula straight off the cake because you'll have many crumbs. You'll need to pull so it doesn't create crumbs. Spread the buttercream over the cake until you have the desired effect.
Add any frosting that's left in the disposable piping bag and pipe swirls around the edge of the cake.