For the Chocolate Frosting (make in advance):
18 ounces semi-sweet or dark chocolate (finely chopped)
2 cups heavy cream
1 cup unsalted butter
For the Chocolate Cake:
1 ½ cups all-purpose flour
1 ½ cup granulated sugar
¾ cup Dutch-processed cocoa powder (sifted)
1 ½ teaspoons baking soda
1 teaspoon baking powder
1 teaspoon salt
2 large eggs
¼ cup vegetable oil
¾ cup buttermilk (room temperature)
2 teaspoons vanilla extract
¾ cup hot water
For the Assembly:
1 cup chocolate flakes or chocolate sprinkles
Large star piping tip
Make the Chocolate Frosting (in advance)
Place chopped chocolate into a large heatproof bowl.
In a medium saucepan, combine heavy cream and butter. Cook on med-high, stirring often, until just simmering.
Pour hot cream over chopped chocolate and cover bowl with plastic wrap. Let sit 5 minutes.
Stir gently until completely smooth.
Place plastic wrap directly on top of chocolate. Allow to thicken and set overnight.*
Make the Chocolate Cake:
Preheat oven to 350F. Grease two 8″ cake rounds, dust with cocoa powder and line bottoms with parchment.
Place flour, sugar, cocoa powder, baking soda, baking powder and salt into the bowl of a stand mixer. Mix until well combined.
In a medium bowl, whisk eggs, oil, buttermilk, and vanilla. Very slowly pour in hot water while whisking constantly.
Add wet ingredients to dry and mix on medium for 2 to 3 minutes. Batter will be very thin.
Pour batter evenly into prepared pans. Bake for approximately 30 minutes or until a toothpick inserted into the center comes out mostly clean.
Place cakes on wire rack to cool for 10 minutes then turn out onto wire rack to cool completely.
Once cooled, cut each layer in half horizontally, if desired.
Assemble the Cake:
Place one layer of cake onto a cake stand or serving plate. Top with a thin layer of chocolate frosting (approximately 2/3 cup). Spread evenly.
Repeat with remaining layers of cake and frosting. Crumb coat the cake. Chill for 30 minutes.
Frost the cake and smooth the sides and top, reserving a small amount of chocolate frosting for the top decorations, if desired. Place cake back in the fridge for 20 minutes to set.
Place a bowl upside-down on a baking sheet. Place cake on inverted bowl so that the sides hang over.
Gently press chocolate flakes (or chocolate sprinkles) into the sides and top.
Pipe dollops of reserved chocolate frosting on top using a large open star tip, like a Wilton 6B, if desired.
Adapted from thecakeblog.com