Chocolate Coffee Fudge Cake

I got a commission! Yes, a full-on paid request for my cake baking work! Two friends of mine had a joint birthday party and asked if I could make the cake. Instead of buying something mundane from a cake shop they preferred a personal touch, and have evidently noticed how much I love baking.
I deliberated for a while over what to do. Basically it came down to something chocolate and gooey. Because, come on, we're talking a party of mainly women here. Chocolate and lots of it is what they want. I decided on the combination of chocolate and coffee because when one of the friends is out for coffee with us, I notice she always orders a mocha. So, a mocha cake for my mocha-loving friend (the other one likes anything. She was easy.)
But I couldn't decide whether I wanted to ice the chocolate cake all around with a dark chocolate fudge icing, and a coffee cream middle, or a chocolate fudge middle and a coffee-flavoured icing around the outside. This dilemma took up more of my attention than you'd expect, and even necessitated serious, survey-type emails to friends. Bascially it came down to this response from A:
"Well, either would work, the big difference would lie in people's reaction:
If it looks like a chocolate cake they will eat it and go: "Ooooh! Nice!"
if it looks like a coffee cake they will ask first and say: "Ooooh! Different! Unusual!" Then eat it and go "oooooh! Niiiice!"
Personally, I wanted to go the coffee coloured outside, but I knew that visuals were everything, and something that was obviously chocolatey would be better. In any case, the coffee/white chocolate icing I tried to make failed miserably and I flushed it down the sink. So, that was that.
I spent some time looking for a really good recipe for the cake and found one on the Baking Sheet site. It included some coffee in the mixture, which I thought would completement the rest of the flavours well. It was a wonderful basic cake; really moist and dark. Thanks Nic!
I sandwiched the two layers with a coffee flavoured cream filling made by creating a coffee essence of instant coffee added to some boiling water mixed in with some whipped cream. Then sprinkled over some walnuts I had caramelised in brown sugar. It was lucky most of them made it onto the cake, because I tell you, homemade caramelised walnuts are pretty darn tasty.

Coffee cream with caramelised walnuts

I then made up the same chocolate fudge buttercream I've used for my two previous chocolate birthday cakes. I also added some strong espresso coffee to the icing, to try and create a mocha flavour. It didn't entirely work, as the most dominant flavour was 'chocolate' and 'sweet'.
I slathered that chocolate goodness over the top of the cake; I actually wasn't able to do all down the sides as there was too much of a gap between the layers so I finely chopped some leftover caramelised walnuts and press them onto the sides, where the cream was showing.

At this stage a friend had popped in to visit and between us we came up with a decorating scheme for the top of the cake. I had bought some great chocolate coffee beans from Haigh's, and a set of beautifully delicate sugar flowers from a baking store, but didn't have much of an idea how I was going to display them. My friend, who does part-time work as a milliner, got creative with the coffee beans, arranging them in snake-like patterns. She insisted that if anybody ask I inform all that all decorating was outsourced!
The picture below shows what it looked like when we had finished, but after that I added a few shiny silver balls to up the elegance stakes a little more.

Yes, everybody loved this cake and made appreciative moaning noises. The party was held in one friend's brand-new house, with no furniture. So we ate this from paper napkins, with our fingers (forks would have been good, but alas no furniture = no cutlery!) sitting on the floor slumped against the wall. Yes, it was rich, but that's what you want with a special-occasion birthday cake, eh?
Also, I have to say, this commission business sounds better than the reality. It took me a looong time to make this cake. I hope the others at the party don't start getting too excited. Once in a while is good, but not every weekend!!
Read on for the recipe:

Chocolate Coffee Fudge Cake

Chocolate Cake
1 3/4 cups plain flour
1 cup white sugar
1 cup brown sugar
3/4 cup unsweetened Dutch-process cocoa powder
2 tsp. baking soda
1 tsp. baking powder
1 tsp. salt
1 1/4 cups buttermilk
2 large eggs, lightly beaten
1/4 cup vegetable oil
1 tsp. pure vanilla extract
1 cup hot strong black coffee
Filling:
300ml whipping cream
2 teaspoons instant coffee
1 tbls boiling water
Caramelised Walnuts
4 tbsp sugar
100 g walnuts (roughly chopped)
Chocolate Fudge Icing
175g dark chocolate
250g unsalted butter, softened
275g icing sugar, sifted
1 tbsp vanilla extract

Preheat oven to 350F.
Whisk together buttermilk, oil, eggs and vanilla. Let the buttermilk mixture come to room temperature. Sift all dry ingredients together in a very large bowl.
Whisk buttermilk mixture into dry ingredients. When combined, carefully whisk in hot coffee.
Pour into greased pans, either 2 9" round cake pans or 1 11x13 pan.
Bake until tester comes out clean, 45-55 minutes depending on the pan (the less batter, the more cooking time).
Note: Do not be fooled by the relative thinness of the batter; it really puffs up as it bakes! Do NOT fill any pans more then 2/3 of the way full!
For the filling: Whip the cream to fairly stiff peaks and make up the coffee extract. Add the extract to the whipped cream and spread over the one cake layer.
For the caramelised walnuts: Heat up a heavy non-stick pan. Pour the sugar in and leave until it liquidises and starts to brown slightly. Turn off the heat and toss the walnuts in the caramel. You will have to work fast as the caramel will continue to cook in the hot pan and you do not want it to burn. Transfer the caramelised nuts to a non-stick baking tray, separate with two forks and leave them to cool. Add to the bottom layer over the coffee cream.
To make the icing, melt the chocolate in the microwave – 2-3 minutes on medium should do it – or in a bowl sitting over a pan of simmering water, and let cool slightly. In another bowl, beat the butter until it's soft and creamy and then add the sieved icing sugar and beat again until everything's light and fluffy. Then gently add the vanilla, hazelnut essence and chocolate and mix together until everything is glossy and smooth. Ice the top and sides of the cake, then apply your decorations.