My aunt Carol gave me this delicious recipe - a fudgy, rich, dark chocolate mud cake with a hint of coffee... Simply too good not to share!
The secret to the success of this recipe lies in the baking. To achieve the moist, fudgy (almost brownie) texture, bake the cake at 140°C (120°C fan) for approximately 60 - 90 minutes. For a four layered cake, divide the cake batter between two 13cm round tins (cutting each layer in half once completely cool). For a two layered cake, divide the cake batter between two 20cm round tins. Layer with dark chocolate ganache and cover with either vanilla Swiss meringue buttercream or more dark chocolate ganache if you wish.
Enough for a tall four layered 13cm round cake or a two layered 20cm round cake (serves approximately 12 - 16)
DARK CHOCOLATE MUD CAKE
250g unsalted butter
150g dark chocolate (70% cocoa solids or more)
440g caster sugar
250ml hot water
80ml coffee liqueur (I've used Kahlua® but any coffee or chocolate-flavoured liqueur will do)
15ml (1 tbsp) instant coffee powder
225g plain/cake flour
35g self-raising flour
25g cocoa powder
pinch of salt
2 large eggs
DARK CHOCOLATE GANACHE
200g dark chocolate (50% - 70% cocoa solids)
200ml cream (approximately 35% fat content)
VANILLA SWISS MERINGUE BUTTERCREAM
150g caster sugar
100g egg whites (approximately 3 large egg whites)
120g icing sugar
220g unsalted butter (at room temperature)
5ml (1 tsp) vanilla bean paste
pinch of salt
To start, line the bottom and sides of two round cake tins with baking paper.
Preheat the oven to 140°C (120°C fan).
Place the butter (roughly chopped), chocolate (broken/chopped roughly), caster sugar, hot water, liqueur and coffee powder in a large heatproof bowl and set it over a medium saucepan of barely simmering water (making sure the surface of the water does not touch the bowl).
Melt the ingredients slowly whisking occasionally until smooth.
In a medium bowl, sieve together all the dry ingredients. Break the eggs into a small bowl and whisk them a little until uniform.
Once the chocolate mixture is smooth, remove the bowl from the heat and whisk in the dry ingredients followed by the two beaten eggs.
Once the batter is smooth, divide between the two prepared tins.
Bake for approximately 60 - 90 minutes (will depend on the tin sizes). Similar to a brownie, a bit of cake/gooey batter sticking to a test skewer is just about right, as long as it is not runny cake batter.
Once baked, remove the tins from the oven and leave the cakes in the tins to cool completely (cover with a clean tea towel to prevent moisture from evaporating).
Once the cakes are cool, make the ganache.
Place the chocolate (broken into pieces or roughly chopped) in a large heat proof bowl.
Place the cream in a small saucepan and heat until it comes to a solid boil. Pour half of the boiling cream onto the broken/chopped chocolate, then leave it for about 10 seconds. Whisk the chocolate/cream mixture until smooth and shiny (usually, not all the chocolate will be melted at this stage).
Reheat the remaining cream until it comes to a solid boil again. Pour the remaining boiling cream over the ganache mixture then whisk again until smooth, uniform and shiny (if by any chance you still have chocolate pieces that are not melted, place the bowl over a medium saucepan of gently simmering water whisking occasionally until all the chocolate has melted).
Allow the ganache to cool slowly at room temperature (a few hours, depending on the weather). It is ready to use to layer the cakes once thick enough to spread or pipe.
To make the Swiss meringue buttercream, place the egg whites and caster sugar in a large heat proof mixing bowl (I use a stainless steel free standing mixer bowl) and set it over a medium saucepan of simmering water (again making sure the surface of the water does not touch the bowl).
Whisk by hand for a few minutes until the sugar has dissolved (you can test this by rubbing a bit of the mixture between your fingers - when ready, is should not feel grainy anymore) and the mixture feels warm to touch (about 65°C on a thermometer if you are unsure). Note: You are not trying to whip the meringue at this stage but instead just dissolve the sugar and cook the egg whites gently.
Remove from the heat and whisk on a high speed with electric beaters or an electric mixer until the meringue is stiff and glossy.
Add the icing sugar (sifted) and beat until uniform (slow at first to prevent being engulfed by a cloud of icing sugar).
If the meringue still feels very warm, slow the mixer to a medium speed and whisk for a few minutes until the mixing bowl is cooler to touch (i.e. the meringue reaches room temperature).
Add the soft, room temperature butter and salt and whisk on a high speed until smooth and glossy (at least 2 - 3 minutes).
(If after several minutes of mixing the mixture seems split, the butter might be too cold - warm the mixing bowl gently using a bain-marie then whisk again on a high speed. If the buttercream looks very runny, the butter or the meringue might be too warm - cool the mixing bowl for a few minutes in the fridge, then whisk again on high).
To assemble the cake (easiest done with a cake turntable, but not essential):
For a four layered, 13cm round cake, divide each cake in two using a sharp bread knife (for a two layered, 20cm round cake, you can keep the cakes as is - they should not have domed too much in the oven, but you can even the top with a knife if needed).
Place the first cake layer on a cake board or serving plate.
Spread or pipe a layer of ganache (avoid spreading or piping the ganache right up to the edges if you are planning on a semi-naked buttercream finish).
Place the second cake layer on top (if making a two layered cake, turn the cake upside down so that the bottom is facing upward to ensure a flat top).
Repeat the layering with the ganache until all the cake layers have been added (finishing with the last cake layer having the bottom facing upwards).
Using a spatula or knife, cover the top and sides with a thin layer of buttercream (this is the crumb coat to trap all the loose cake crumbs, so do not stress if there are a few crumbs visible in the icing).
Refrigerate the cake for about 10 minutes until the buttercream is firm.
Coat the top and sides of the cake for a second time (thin if you prefer the semi-naked finish or thicker if you want the cake completely covered).
For a sharp finish, use a dough/cake scraper to smooth the sides..
Flatten the top ridge by scraping with a spatula or scraper in an inward motion.
Decorate the cake with edible gold or silver leaf and/or fresh seasonal flowers.