To make the chocolate cake layers:
To make the cake, preheat oven to 350°F. Butter and flour two or three 8-inch or 9-inch cake pans (see Notes) and line bottoms with parchment paper.
In a large bowl, sift together the flour, sugar, cocoa powder, salt, and baking soda.
In another bowl, whisk together eggs, sour cream, and vegetable oil. Add coffee and whisk until smooth.
Add wet ingredients all at once to the dry ingredients and whisk until no streaks of dry ingredients remain. Do not overmix.
Divide the batter evenly between the prepared cake pans and bake until a toothpick inserted into the center comes out clean, about 25-35 minutes (see Notes). Let cool in the pan for 10 minutes, then remove and place on a wire rack to cool completely.
To make the chocolate ganache:
Add chocolate to a microwave-safe bowl. Heat heavy cream until steaming and then pour over the chocolate. Let it sit for 5 minutes, then stir until smooth.
If a few lumps of chocolate remain, heat in the microwave in 15-second bursts, stirring in between to see if ganache is smooth.
Let ganache cool to room temperature while you make the frosting.
To make the fudge buttercream frosting:
To assemble the cake:
Place one cooled cake layer onto a plate or cake stand. Spread about 1 cup fudge buttercream frosting on top, and cover with about ½ cup of the ganache. Repeat with remaining cake layers and filling. (Filling amounts are for a 4-layer cake. If you are doing only 2 or 3 layers, you can be more generous with the frosting and ganache.)
Cover entire cake with remaining fudge frosting. Top with remaining ganache, letting it drip down the sides as desired. Chill in fridge for at least 1 hour to firm up. Let cool to room temperature 30 minutes before serving.
NOTES
- Coffee helps enhance the chocolate flavor of the cake. The cake will not have a coffee taste. You can brew coffee for this recipe, or combine 1¼ cup hot water with 2 teaspoons instant espresso.
- I used Hershey's Special Dark cocoa for this cake.
- Which size cake pan and how many you choose to use is up to you and the look you want. 8-inch pans will yield a taller, narrower cake than 9-inch pans. Do not fill cake pans more than 2/3 full or they may overflow in the oven.
- Bake time will vary based on pan size and how much batter is in the pan. Time listed in this recipe is for cakes baked in 2 8x3-inch pans. Cakes baked in 9-inch pans or more than 2 8-inch pans will bake faster. Start checking at 20 minutes. When they appear dry on top, open the oven and gently press with your finger. Cakes are done when they feel firm but bounce back, and a toothpick inserted comes out with moist crumbs.
Calories: 887kcal, Carbohydrates: 116g, Protein: 10g, Fat: 48g, Saturated Fat: 30g, Polyunsaturated Fat: 2g, Monounsaturated Fat: 12g, Trans Fat: 1g, Cholesterol: 134mg, Sodium: 477mg, Potassium: 437mg, Fiber: 6g, Sugar: 84g, Vitamin A: 1150IU, Vitamin C: 0.4mg, Calcium: 128mg, Iron: 5mg