What does one do when they have the house to themselves all day….? Cook a chocolate Rubik’s Cube cake…obviously.
Dark Chocolate Mud Cake
225g unsalted butter, chopped into cubes
360g chopped dark chocolate
1 tbsp instant coffee granules
3/4 cup water
3/4 cup brown sugar
1 cup plain flour
1/4 cup self-raising flour
1/4 cup coffee or chocolate liqueur
Preheat oven to 150 °C.
Place butter, chocolate, coffee, water, and sugar in a metal bowl; place bowl over a saucepan of simmering water (or use double boiler) and stir until everything is melted and combined. Leave the mixture for about 15 minutes, or until cool.
Whisk the sifted flour and liqueur into the mixture until smooth and combined.
Pour the mixture into a lined, 18cm, square pan. Tap the pan a couple of times on the bench to settle the mixture.
Bake the cake for about 90 minutes (check using a skewer -if skewer is clean after being inserted into the cake, the cake is cooked).
Allow cake to cool in the pan.
The cake is super easy – it does take a while though because everything has to be completely cool before you move on to the next stage (this does give you enough time to re-watch the entire 4th season of How I Met Your Mother though…so really…win).
While I was waiting for the cake to cool I made some chocolate ganache to ice it with. Ganache has a reputation of being really hard, which I imagine it is if you care about it being perfect as opposed to just caring about whether it tastes delicious. Basically boil 1/2 a cup of cream on the stove top (add any food colouring you want, black in this case) and then pour this on top of 200g of chopped dark chocolate and stir until the chocolate melts. Sometimes the ganache splits (goes all grainy), but I have found that if you just stick it in the fridge for a bit and then beat the hell out of it in the Kitchen Aid it will still turn out awesome.
I then made some fondant squares for the sides of the cube. I coloured the fondant by kneading in gel food colouring and adding cornflour to adjust the texture (I also coloured my hands for the rest of the day…). I then cut 3x3cm squares and left them to dry for about an hour.
When the cake was FINALLY cool, I levelled the cake with a bread knife, just cutting the top off so the cake sits level (tip: cool the cake upside down so the cake is already pretty flat). I then cut it into quarters (i.e. 4, 9×9 cm pieces), ate one quarter as a reward for my hard work, then stacked the other three pieces on top of each other to form a cube, squirting a bit of icing in between each layer to hold it together.
I then iced my cake tower with a thin layer of the ganache, piping it on and then smoothing it with a spatula. I also rotated the top layer so it looked like someone was trying to solve the cube. I stuck it back in the fridge for a bit for this layer to set, thus preventing crumbs getting mixed up with the icing. When it was cool, I piped and smoothed on another layer of icing and pressed the fondant squares into the sticky icing. When I had finished all the sides I piped a thin line of the ganache between the squares to define the edge. To be honest piping is my Achilles Heel in baking; I have a shaky hand and the inability to maintain the same pressure throughout so I end up with a wonky line with 7 different thicknesses.
I’m pretty happy with the final product – it definitely looks like a Rubik’s cube and it is totally delicious, so I fulfilled the brief. However, if I were to do it again, I would cover the whole cake in black fondant rather than icing – this would mean I don’t have those annoying chocolaty finger prints on the squares and I wouldn’t have to attempt any piping.
In the end, like all the others before it, I couldn’t solve this Rubik’s Cube.
Cake recipe adapted from Australian Women’s Weekly Cake Decorating book.