Devil's Food Cake with Chocolate-Chip Buttercream

Last Monday, our tiny five-person Japanese class had a party to signify our last lesson with our on/off Japanese teacher who was going on maternity leave. As these weren't my usual taste tasters, I decided on something simple yet effective; yes, another chocolate cake! I knew the Old-Fashioned Chocolate Cake recipe was a reliable one, but I decided I would instead use this opportunity to try out a recipe for Devil's Food Cake. I have never made one of these before (or indeed, eaten one), so I was intrigued by what this recipe, which included half a cup of coffee, would produce.
The result was a cake with a deep, dark chocolate flavour (yeah, nine tablespoons of cocoa powder tends to do that :P), and was less rich/sweet than the chocolate cakes I was used to making. The large amount of cocoa powder, as well as the coffee, made the cake a beautiful, deep, dark chocolate colour to match its flavour, and I thought the white buttercream would be a good contrast.
This recipe is David Lebovitz's, but the one I directly used was from raspberri cupcakes. I didn't make the icing mint flavoured, but I liked the idea of a buttercream speckled with chocolate.
The cake itself was lovely, but I think next time I would try a regular chocolate ganache (like on Lebovitz's original recipe), as the buttercream seemed out of place on this cake.
I wish I'd had gotten a picture of the inside of the cake when we had cut it, the contrast looked really good.
Oh well, here's the recipe, folks! 

Oh! And as always, I made the buttercream quantities based on my own judgement, but I'll include the measurements from raspberri cupcakes... Although it seems to be a lot more than I used.

(Adapted from David Lebovitz's Devil's Food Cake recipe)

For the cake: 

•  9 tbsp cocoa powder
• 1 1/2 cups cake flour (you can just measure out that amount of plain flour and replace three tablespoons with cornflour instead)
• 1 tsp baking soda
• 1/4 tsp baking powder
• 115g soft unsalted butter
• 1 1/2 cups caster sugar
• 2 large eggs
• 1/2 cup strong coffee
• 1/2 cup milk

For the chocolate-chip buttercream

• 280g soft butter
• 500g icing sugar
• 150g dark chocolate, grated
• 2 tsp vanilla essence

1. Preheat oven to 180 degrees and grease two 20cm cake tins (I only have one so I had to do them one after another).
2. Sift together the cocoa powder, flour, salt, bicarb soda, and baking powder in a bowl.  
3. Cream the butter and sugar together with an electric mixer until light and fluffy.
4. Add the eggs, one at a time, and beat until combined.
5. Mix together the coffeee and the milk.
6. Pour in half of the dry ingredients into the butter mixture, stirring to combine.
7. Add the coffee and milk into the mixture.
8. Finally, add the last of the dry mixture and stir untl combined.
9. Divide  mixture between the two tins (if only using one, reserve half the mixture in a small, covered bowl).
10. Bake for 20-25 minutes  or until a skewer inserted into the centre of the cake comes out clean. 
11.  Allow cake to cool for five minutes in its tin before transferring to a wire rack to cool completely.
12. (If using one tin, put other half of mixture into tin after removing the cooked cake and repeat) 
13. When cakes are completely cool, prepare the buttercream by mixing the butter and the vanilla essence  with an electic mixer until smooth and creamy.
14. Sift in the icing sugar, a cup at a time, beating after each cup until all the icing sugar is used and the buttercream is fluffy and thick. 
15. Add the grated chocolate to the mixture , giving it a quick whiz on low speed to distribute the chocolate into the buttercream.
16. Sandwich cakes together with icing and then cover entire cake with icing; decorate top of cake with additional grated chocolate if desired.