20regular Oreosfinely crushed (I recommend using a blender or food processor)
Chocolate Ganache Drip
4ouncessemi-sweet chocolatechopped (113 grams)
½cupheavy whipping cream(120 ml)
Instructions
To make the chocolate cake: Preheat the oven to 350°F (180°C). Spray three 8-inch round cake pans with nonstick cooking spray, line the bottom of each pan with parchment paper, and set aside.
In a large mixing bowl, sift the flour, cocoa powder, baking soda, baking powder, and salt together. Whisk in the granulated sugar and brown sugar until well combined.
Add the oil, buttermilk, eggs, and vanilla extract and mix until just combined, the batter should be thick like brownie batter.
Add the instant espresso powder to the cup of boiling water and mix until fully dissolved. Add to the mixing bowl and mix until just combined and smooth, the batter will be very thin.
Divide the batter evenly between the three prepared cake pans.
Bake for 25 to 30 minutes or until a toothpick inserted into the center of the cakes comes out clean and the tops spring back when lightly touched.
Remove from the oven and transfer to a wire rack to cool in the pans for 20 to 30 minutes. Run a knife around the outside of each cake layer in the pan then carefully remove the cakes from the pans (peel off the parchment paper, if needed) and place on the wire rack to cool completely.
To make the Oreo buttercream frosting: In the bowl of a stand mixer fitted with the paddle attachment, or in a large mixing bowl using a handheld mixer, beat the butter on medium speed for about 1 minute or until smooth.
Mix in 2 cups (240 grams) of powdered sugar at a time, making sure to mix well after each addition.
Add the heavy whipping cream, vanilla extract, and salt and mix on medium speed until the mixture is well combined and creamy.
Add the Oreo crumbs and mix on low-medium speed until well combined, stopping to scrape down the sides of the bowl as needed.
To assemble the cake: Level the tops of each cake layer with a knife or cake leveler.
Add a tablespoon of buttercream to the center of a cardboard cake round or a cake stand to help the cake stick to the surface.
Place the first layer of cake onto your work surface. Scoop ¾ cup to 1 cup of frosting onto the first layer of cake and spread it around into one even layer with an angled spatula or the back of a spoon.
Place the second cake layer upside down on top of the frosted cake layer. Spread another ¾ cup to 1 cup of frosting on top and spread it around into one even layer.
Place the third cake layer upside down on top of the frosted cake layer. Use the remaining frosting to frost the top and sides of the cake. If piping some decorations on top, reserve 1 to 1 ½ cups of frosting for later.
Place the cake in the refrigerator and let it chill while you prepare the ganache.
To make the ganache (optional): Add the chopped chocolate to a large heatproof bowl and set aside.
Add the heavy whipping cream to a microwave safe bowl (or a glass measuring cup) and heat in the microwave for 45 seconds to 1 minute. Make sure to keep an eye on it so it doesn't bubble over in the microwave.
Pour the warm heavy whipping cream over the chocolate and let it sit for 2 to 3 minutes. Start stirring slowly in the middle of the bowl, and continue stirring in one direction until the mixture is smooth and well combined.
Set aside for 20 to 30 minutes or until the mixture has cooled and thickened slightly.
Remove the cake from the refrigerator. Add the ganache to a piping bag or a squeeze bottle (or simply use a spoon) and add drips all around the top edge of the cake. Add the remaining ganache on top and spread it around into one even layer.
Allow the ganache to firm up slightly, then pipe the reserved frosting on top of the cake. Top with additional Oreos, if desired.
Video
Notes
Storage Instructions: Once frosted and assembled, the cake can be stored in an airtight container and refrigerated for up to four days. Freezing Instructions: The unfrosted cake layers and Oreo frosting can be frozen for up to three months in separate containers. Thaw overnight in the refrigerator and bring the frosting to room temperature before assembling the cake.