Preheat the oven to 350F/177C. Line two, 8-inch (20-cm) cake pans with parchment paper. You can also use two, 9-inch (23-cm) cake pans but your cake layers will be slightly shorter.
Into a large mixing bowl, add the buttermilk, cooking oil (I use canola oil), sugar, eggs, and vanilla. In a separate, small ramekin, combine the instant coffee and hot water. Stir to dissolve the coffee, then add it into the mixture. Using a mixer, beat everything together for a few minutes, until the eggs are well beaten.
Next, melt the dark chocolate in the microwave until it’s smooth. Wait a few minutes for the chocolate to cool slightly, then pour it into the batter and mix for about a minute.
In a separate bowl, combine all the dry ingredients: flour, cocoa powder, baking soda, baking powder, and salt. Sift the dry ingredients into the batter first, then beat on low-medium speed for about 2 minutes, until a smooth cake batter forms.
Baking the Cake:
I like to use a kitchen scale to split the cake batter evenly between the two prepared pans. Use an off-set spatula to smooth the batter, creating even cake layers.
Bake the cake layers at 350F/177C for 30 to 35 minutes, until a toothpick inserted into the center comes out clean.
Remove the layers from the oven and wait about 5 minutes before removing the cake layers from the pans. Allow the cake layers to cool completely on a wire rack. You can place the layers on the wire rack into the refrigerator to cool faster.
Cream Cheese Frosting:
While the chocolate cake is baking and cooling, it’s the perfect time to make a batch of my ‘Dark Chocolate Cream Cheese Frosting’. Find those instructions below.
Making Chocolate Ganache:
To make the ganache, simply combine the chocolate chips and heavy cream together in a large measuring cup. Heat the chocolate in 30 second intervals, stirring after each interval, until the chocolate is smooth and melted.
The ganache will be hot and thin/runnier at first. Allow it to cool at room temperature, stirring occasionally, until it cools and thickens. Don’t use hot ganache on the cake; this will melt the frosting!
Assembling the Cake:
Make sure the cake layers are completely cooled, otherwise the frosting will melt! Using a sharp, serrated knife, level off the top of each cake layer, then split each layer in half, resulting in 4 layers total.
Start by pouring a few tablespoons of the chocolate ganache onto each cake layer. Use an off-set spatula to help the chocolate sink into the cake layer. Top each layer with a generous about of chocolate frosting and level the frosting before adding the next layer.
For the top layer, spread the ganache onto the openside of the cake first, then invert it onto the top. Next, cover the cake with a crumb coat of frosting. This thin layer of frosting will seal in all the crumbs. Refrigerate the cake after frosting for about 20 minutes.
Apply a final, thicker layer of chocolate frosting last, smoothing it with cake spatulas.
I start by garnishing the sides of the cake with chocolate sprinkles. Place the cake, on a cake stand/turn table, onto a large baking sheet. The sheet will catch all the sprinkles. Gently press the sprinkles into the sides of the cake.
Pour the remaining cooled chocolate ganache over the sides of the cake first, then fill in the top. I recommend refrigerating the cake for about 15 minutes after adding the ganache and before garnishing the top.
Transfer the remaining chocolate frosting (usually about 1 ½ cups) into a pastry bag tipped with a star tip. I used Ateco #847. Pipe dollops of frosting on top of the cake. If desired, add chocolate squares on top.
Storing & Serving:
This dark chocolate cake is best served when it’s at room temperature. A cold cake will be more dry and more crumbly. If you needt o refrigerate the cake overnight, take it out a few hours prior to serving to allow it to soften and warm back up.
Store the cake in the refrigerator overnight for best results. If you have a few slices left over, you can place them into an airtight container and into the freezer.
For Cream Cheese Frosting:
The most important step for making this chocolate frosting happens before you start the recipe! Softening the butter and cream cheese properly is very crucial for optimal results. If the butter or cheese is too soft, the frosting will stay flat and greasy. Remove the butter and cream cheese from the refrigerator approximately 45 minutes before beginning the recipe. Set them onto your kitchen counter to soften. The butter and cream cheese should be just slightly softened but still have a firm core. Do not use melted butter!
Next, prepare the melted chocolate. Place the chocolate chips into a microwave safe bowl and heat the chocolate on a medium power setting to avoid burning the chocolate. Stir it every 45 seconds until the chocolate is smooth and creamy. Allow the chocolate to cool slowly at room temperature, stirring it occasionally. Do not add hot melted chocolate into the frosting! This will melt the butter, making the frosting too soft.
To prepare the instant coffee flavoring, place the instant coffee into a small ramekin and pour over the boiling water. Stir until the coffee is completely dissolved. Allow this concentrated coffee to cool completely; you can place it into the refrigerator to cool faster. Do not add hot coffee into the frosting!
Place the softened butter into a stand mixer bowl with the flat beater attached. A hand mixer will also work well but will require extra mixing time. Beat the butter on medium then high speed for about 4 minutes, until it’s light and fluffy. Scrape down the sides of the mixing bowl midway.
Next, add the cream cheese. Continue mixing on medium-high speed for another 4 minutes, until the mixture is smooth. Add in the cooled coffee, vanilla extract, and heavy cream next and mix for about 30 seconds; briefly, just until the extract is incorporated. Next, add in the cocoa powder, cooled melted chocolate, and salt. Mix again for about 30 seconds.
Finally, add in the confectioner’s sugar. Start the mixer out on a slow speed to keep the sugar from flying everywhere, then increase the speed to ‘high’ and beat for 3 to 4 minutes, until the frosting is extra fluffy. It will start to become lighter in color, too as it mixes.
If your cream cheese frosting is too soft and not pipeable, simply place the mixing bowl into the refrigerator and allow the frosting to chill for about an hour. Give it a mix for about a minute on low speed once its chilled, then use.
Nutritional facts are calculated with chocolate sprinkles and chocolate squares used for garnish.