FOR THE CAKE

1. Preheat the oven to 350 degrees Fahrenheit. Cover the bottoms of two circular cake pans measuring 8 inches in diameter with parchment paper discs and butter them.
2. To thoroughly combine all of the dry ingredients, whisk them together in a large basin.
3. Put all of the wet ingredients, with the exception of the coffee, into a separate bowl and whisk them together.
4. It is important to combine the dry components as you slowly add the wet elements to the dry ingredients. After the ingredients have been combined, pour in the hot coffee and continue to stir everything together until there are no dry flour pockets remaining. The batter is going to be pretty thin.
5. The mixture should be divided between the two cake pans, and the cakes should be baked for thirty-five minutes, or until the cake has risen and a toothpick put into the center of the cake can be removed without any wet batter clinging to it.
6. Take the cakes out of the pans and allow them to cool somewhat before turning them out onto a cooling rack to finish cooling completely before icing them. In order to prepare the cakes for icing, they can be prepared a day or two in advance and stored in the refrigerator.

FOR THE FROSTING

1. Either in a microwave using brief bursts or in a double boiler, melt the chocolate until it is smooth. After stirring until smooth, set aside to cool down a little bit.
2. Beat the butter that has been at room temperature for a couple of minutes in the bowl of a stand mixer fitted with the paddle attachment until it is completely smooth and visibly lighter in color. While beating on a low-to-medium speed, gradually include the powdered sugar, salt, and vanilla extract until everything is completely smooth.
3. Whisk the sour cream into the chocolate that has been partially melted and let to cool. During this process, the chocolate is cooled down, and the sour cream is warmed up, such that both of them are at a temperature that is close to room temperature before being added to the butter mixture.
4. After adding the chocolate and sour cream combination to the bowl of the mixer, reduce the speed to low and continue beating until everything is completely smooth and cohesive.
5. In the event that your frosting appears to be a little too loose, you may place it in the refrigerator for ten to fifteen minutes to allow it to become somewhat more rigid. After that, give it a thorough swirl before proceeding to frost the cake.