For the Cake:

1. Preheat the oven to 350°F. Prepare three 8-inch round baking pans, line the bottom with parchment paper, and grease the sides. Prepare your bake even stripes if desired.
2. In a large mixing bowl, combine the sugar, vegetable oil, eggs, and vanilla extract. Beat on medium speed until the eggs and oil are well incorporated and the batter is lighter in color. Next mix in the sour cream and beat until well combined.
3. In a separate bowl, sift together the dry ingredients. Add half the dry ingredients to the wet ingredients, followed by half of the coffee, and mix until the flour is just incorporated at a low speed. Then add the remaining dry ingredients and coffee. Beat until all of the ingredients are well combined. Use a spatula to scrape down the sides of the bowl and stir the batter from the bottom to the top to ensure it’s well mixed.
4. Divide the batter evenly between the three pans, about 1 2/3 cups of batter per pan. Bake at 350°F for 20-24 minutes.  Test the cake for doneness by inserting a toothpick into the center of the cake. If the toothpick comes out clean, the cake is done. Remove from the oven and allow to cool completely.

For the Frosting:

1. Microwave 2 tablespoons of heavy whipping cream for 30 seconds to warm, then dissolve 1 tablespoon of instant espresso into the cream. Place in the freezer to quickly cool it down and ensure it’s chilled before adding it to the frosting.
2. Cut the cold butter into tablespoon-size pieces. Using the paddle attachment, whip the butter for 5-7 minutes, scraping down the bowl occasionally until the butter is whipped and easily spreadable.
3. Add 3 cups of powdered sugar, salt and the vanilla extract and beat at a medium-high speed until well combined, then beat for another 1-2 minutes.
4. Next, add 3 more cups of powdered sugar with heavy cream and espresso mixture plus the remaining  1 1/2 tbsp espresso powder. Beat on low speed until sugar is incorporated.
5. Add the remaining 2 cups powdered sugar with the remaining 1 tablespoon heavy cream, beating until combine then Increase speed to medium-high and beat for another couple of minutes. Use immediately or store.

To Assemble

1. Level the cake layers if needed. Place a dollop of frosting on your cake board and place the bottom layer of cake on top of that. Place half of the frosting in a large piping bag, then cut off the end of the piping bag.  Pipe the first layer of frosting, pipe in circles working outside edge to the middle. Spread evenly with an offset spatula.
2. Add the second layer of cake and add the remaining frosting. Place the third layer of cake on top, and invert the top layer.
3. Use the piping bag to fill in any gaps between the layers and to create a crumb coat. Using an offset spatula or icing smoother, wipe away the excess frosting, leaving you just enough to coat the outside of the cake. With the remaining frosting, pipe the frosting along the outside edge of the cake using a large open round tip, or a cake icer tip. Then use an offset spatula to smooth the edges. Save leftover frosting to pipe the rosettes on top of the cake.
4. Chop the dark chocolate into thin and small pieces and gently press it into the sides of the cake and sprinkle on top.