Preparation

Step 1: Bake the Chocolate Cake

1. Preheat your oven to 350°F (175°C) and prepare two 9-inch round cake pans by greasing and flouring them.
2. In a large mixing bowl, whisk together flour, sugar, cocoa powder, baking powder, baking soda, and salt.
3. Add buttermilk, vegetable oil, eggs, and vanilla extract to the dry ingredients. Mix until well combined.
4. Slowly pour in the hot coffee, mixing until the batter is smooth.
5. Divide the batter evenly between the pans and bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
6. Allow the cakes to cool completely before assembling.

Step 2: Prepare the Chocolate Mousse Filling

1. Place the chopped chocolate in a heatproof bowl.
2. Heat ½ cup heavy cream until it just begins to simmer, then pour it over the chocolate. Let it sit for 1 minute before whisking until smooth. Allow the mixture to cool slightly.
3. In a chilled mixing bowl, whip the remaining 2 cups of heavy cream with powdered sugar and vanilla extract until stiff peaks form.
4. Gently fold the cooled chocolate mixture into the whipped cream until fully combined.

Step 3: Make the Chocolate Buttercream Frosting

1. In a large bowl, beat the softened butter until smooth and creamy.
2. Gradually add powdered sugar and cocoa powder, alternating with heavy cream, and beat until the frosting is light and fluffy.
3. Stir in the vanilla extract.

Step 4: Assemble the Cake

1. Place one chocolate cake layer on a serving plate. Spread a generous layer of chocolate mousse filling over the cake.
2. Top with the second cake layer and frost the entire cake with the prepared chocolate buttercream frosting. Smooth the sides and top with a spatula.

Step 5: Create the Ganache Drip

1. Place the chopped chocolate in a heatproof bowl.
2. Heat the heavy cream until it begins to simmer, then pour it over the chocolate. Let it sit for 2 minutes before stirring until smooth.
3. Allow the ganache to cool slightly until it thickens but is still pourable.
4. Pour the ganache over the top of the cake, letting it drip elegantly down the sides.

Step 6: Decorate with Chocolate Overload

1. Arrange chocolate shavings, curls, brownie bites, truffles, mini chocolate chips, and candies on top of the cake and around the base. Get creative with the arrangement for a dramatic effect.

Step 7: Chill and Serve

1. Refrigerate the cake for at least 2 hours, or until the mousse and ganache are fully set.
2. Slice and serve this decadent chocolate masterpiece chilled for the best experience.