To Make the Cake:

1. Prepare three 8 inch cake pans with parchment paper circles in the bottom and grease the sides. Preheat oven to 350°F (176°C).
2. Combine the flour, cocoa powder, baking soda and salt in a medium sized bowl and set aside.
3. Add the butter, oil, brown sugar and vanilla extract to a large mixer bowl and beat together on medium speed until light in color and fluffy, about 2-3 minutes. Do not skimp on the creaming time.
4. Add the eggs one at a time, mixing until mostly combined after each. Scrape down the sides of the bowl as needed to be sure all ingredients are well incorporated.
5. Add the sour cream and mix until well combined.
6. Add the milk and mix until well combined. The batter may look a little stringy or separated. That’s ok.
7. Add half of the dry ingredients to the batter and mix until mostly combined.
8. Carefully add half of the coffee and mix until well combined.
9. Add the remaining dry ingredients and mix until well combined and smooth. Scrape down the sides of the bowl as needed to be sure all ingredients are well incorporated.
10. Add the remaining coffee and mix until well combined and smooth. Scrape down the sides of the bowl as needed to be sure all ingredients are well incorporated. Do not over mix the batter.
11. Divide the batter evenly between the cakes pans and bake for 23-27 minutes, or until a toothpick comes out with a few crumbs.
12. Remove the cakes from the oven and allow to cool for about 2-3 minutes, then remove to cooling racks to cool completely.

To Make the Chocolate Buttercream:

1. Add the butter to a large mixer bowl and beat until smooth and creamy.
2. Add the melted chocolate in three parts, mixing until well combined after each addition. Adding the melted chocolate slowly will help avoid having chunks of chocolate form.
3. Add the cocoa powder and about half of the powdered sugar and mix until well combined
4. Add the salt and half of the heavy cream and mix until well combined.
5. Add the remaining powdered sugar and mix until smooth.
6. Add the remaining heavy cream as needed to get the right consistency of frosting.

To Assemble the Cake:

1. To put the cake together, use a large serrated knife to remove the domes from the top of the cakes so that they’re flat. These cakes don’t have a large dome, but I like to make sure they’re completely flat.
2. Place the first cake on a serving plate or a cardboard cake round.
3. Spread about 1 cup of frosting evenly on top of the cake.
4. Add the second layer of cake and another cup of frosting.
5. Top the cake with the remaining layer and frost the outside of the cake. Refer to my tutorial for frosting a smooth cake, if needed.
6. Use an offset spatula to create designs in the side of the cake’s frosting, if desired. To see how I do the design shown, see the video above.
7. Sprinkle additional chopped chocolate around the outer edge of the cake, if desired, then serve.
8. Store in an air-tight container. The cake is best if eaten within 3-4 days.