Step 1: Prepare the Cake Batter
- Preheat the Oven: Set oven to 350°F (175°C). Grease and flour three 9-inch cake pans. Use cake strips for even baking.
- Mix Dry Ingredients: Sift together flour, sugar, cocoa powder, salt, baking soda, and baking powder in a stand mixer’s bowl.
- Combine Wet Ingredients: In a separate bowl, mix sour cream, buttermilk, eggs, coffee, water, and oil.
- Combine Mixtures: Gradually add wet ingredients to dry ingredients, mixing on medium speed for 2 minutes.
Pro Tip: Ensure ingredients are at room temperature for a smoother batter.
Step 2: Bake the Cake Layers
- Pour Batter: Divide the batter evenly among the pans.
- Bake: Place pans in the oven and bake for 35–40 minutes. Rotate pans halfway through. Use a toothpick to check doneness.
- Cool: Let cakes cool for 5 minutes in pans, then transfer to wire racks.
Common Mistake: Overbaking can result in a dry cake. Check a few minutes early if your oven runs hot.
Step 3: Make Mocha Buttercream
- Whip Butter: In a mixer, whip butter until creamy, about 5 minutes.
- Add Dry Mix: Gradually add confectioners sugar, cocoa, espresso powder, and salt, mixing slowly.
- Finish Buttercream: Add vanilla and cream, beating until smooth.
Pro Tip: Adjust espresso powder for desired strength.
Step 4: Prepare Ganache
- Heat Cream: Warm heavy cream and pour over chopped chocolate. Let sit for 2 minutes, then whisk until smooth.
Pro Tip: Microwave briefly if chocolate doesn’t fully melt.
Step 5: Assemble the Cake
- Layer: Place the first cake layer on a plate, spread buttercream, add ganache swirl, and sprinkle espresso beans.
- Repeat: Continue with remaining layers.
- Frost: Cover entire cake with buttercream, smoothing with an offset spatula.
- Decorate: Drizzle ganache over cake, and pipe buttercream dollops on top. Place an espresso bean on each dollop.
Common Mistake: Overfrosting can cause slippage. Keep layers even and stable.