In a small bowl, whisk together the flour, sugar, cocoa powder, espresso powder, baking powder, and salt. Set aside.
In a separate large bowl, whisk together the vegetable oil, eggs, milk, and vanilla.
Brew the espresso or coffee right before this step so that it's very hot! Slowly drizzle in the hot espresso while continuously whisking. [It's important to go slowly so that the eggs come up to temperature gradually and don't scramble.]
Gently mix in the dry ingredients until just combined. The batter will be thin.
Evenly spray each cake pan with an oil based pan spray.
Pour ⅓ of the batter into each cake pan (they will only be about half full).
Bake at 350°F for 25-30 minutes or until a cake tester comes out clean.
Place a cooling rack on top of each cake pan and invert. The pan should slide cleanly away.
Let the cakes cool completely to room temperature before trimming.
Once the cakes are fully cooled. Using a sharp bread knife, trim the cakes until the layers are even. Wrap each layer tightly in plastic wrap and place in the freezer overnight (minimum 30 minutes).
Chocolate Buttercream
In a large bowl using a handheld or stand mixer fitted with a paddle attachment, cream the room temperature butter and powdered sugar until smooth.
Add in the cocoa powder, espresso powder, and salt and mix until fully combined.
Then slowly add in the cream until combined.
Beat the frosting on high for 4-5 minutes until light and fluffy.
Assemble the Cake
Remove cake layers from the freezer. Place the bottom layer of cake on your cake stand and spread about ¼ of the chocolate buttercream on top and smooth into an even layer.
Then top with the next layer and repeat. Place the final cake layer upside down so that the top of your cake is as even as possible.
Smooth a small amount of the buttercream on the top and sides of the cake. Then place the cake in the freezer for about 20 minutes.
This is the crumb coat and helps the rest of the buttercream go on in a smooth layer!
Smooth the rest of the buttercream on the top and sides of the cake. Don't worry if it isn't perfect because the chocolate ganache will cover the top!
Place back in the freezer for another 20 minutes before pouring the ganache on top. This is important for getting the ganache to solidify while dripping!
Chocolate Ganache
Finely chop the dark chocolate and place into a large bowl.
Place the heavy cream in a microwave safe bowl and microwave for 1-2 minutes or until hot to the touch but not boiling.
Pour over the chopped chocolate and let sit for about two minutes.
Using a spatula, gently mix until the chocolate is fully melted and the ganache is fully combined and smooth.
The ganache should be a smooth, pourable consistency.
Remove the cake from the freezer and pour the ganache on top. Use an offset spatula to gently push some of the chocolate off the edges to create the drip effect.
Place the cake back in the freezer for another 10-15 minutes so that the ganache can fully set.
Store the cake in the fridge until ready to serve.
Notes
This recipe is designed for 3 six inch cake pans. It will also work with 2 eight inch cake pans.
Store the cake in the fridge for up to 4 days. However, it will taste best when served at room temperature! I like to let it sit at room temperature for about an hour before serving.
Freeze any leftover buttercream for up to 3 months, just place in the fridge overnight to thaw.