CAKE: Preheat oven to 350°F. Grease three 9″ round cake pans and line bottoms with parchment paper or lightly flour.
In a medium bowl, whisk together eggs, buttermilk/sour milk, hot coffee*, vegetable oil, and vanilla.
Combine flour, sugar, cocoa powder, baking soda, baking powder, and salt in a large bowl and whisk together. Add wet ingredients to dry ingredients and whisk until incorporated. Beat batter on medium-low speed, 2 minutes, until well combined and smooth. (Do not overmix batter by beating on high speed.) Divide batter evenly among pans.
Bake for 35 to 40 minutes, or until a toothpick inserted into the centre comes out clean. For even baking, rotate pans front to back halfway through. Allow to cool in pans for 10 minutes before turning onto a rack to cool completely.
ASSEMBLE: Fill the cooled cakes with Fudge Frosting. Mask the outside of cake with Chocolate Cream Cheese Buttercream. Chill cake in fridge 20-30 minutes; pour most of the Chocolate Ganache Glaze on the centre top; gently spread glaze to the edges with a spatula until it begins to seep over the edges of the cake. Garnish the top with brownie chunks and dark chocolate chips; drizzle the top with remaining glaze. Serve at room temperature.
FROSTINGS & GARNISHES INSTRUCTIONS
DARK CHOCOLATE FUDGE FROSTING
In a medium bowl, whisk together the icing sugar, cocoa powder, and salt.
Cream the butter on medium-high speed until light and fluffy, about 3 minutes. On medium-low speed, alternately add the icing sugar mix in 3 additions and the milk in 2 additions, beginning and ending with the icing sugar; beat after each addition until fully incorporated. Increase speed to high and beat for 3 more minutes.
Use immediately or store in airtight container in the fridge up to 1 week.
CHOCOLATE CREAM CHEESE BUTTERCREAM
Cream together butter and cream cheese until smooth.
Whisk together icing sugar and cocoa powder; gradually add about half to butter mixture. Add vanilla. Beat in 1 – 2 tablespoons of milk. Add rest of icing sugar mixture and alternate added milk until the buttercream reaches a thick, spreadable consistency.
CHOCOLATE GANACHE GLAZE
In a medium saucepan, bring an inch or two of water to a simmer.
Combine the chocolate, butter, corn syrup, and vanilla in a large heat-proof bowl and set over the simmering water. Gently and continuously stir until chocolate and butter are melted and glaze is smooth. remove bowl from pot and allow glaze to cool to room temperature.
Use immediately or store in airtight container at room temperature up to 1 week.
* For a smooth glaze, use while it is still warm to touch and runny; for a spreadable frosting-like texture, let thicken and cool fully to room temperature.