This chocolate cake is a firm family favourite.  It is more like a mixture between a mouse cake and brownie than a traditional chocolate birthday cake but the flavour is amazing and everybody loves it.  The key to any birthday cake feeling like a success is down to the decorations and here you should absolutely buy what you need.  I do like most of the decorations to be edible but the best 'bullets' are from the toy section. 

This cake will need to fully cool and that will take several hours so day 1 make the cake and the buttercream and day 2 assemble.  This cake is so moist and gorgeous that leaving it a day will not be a problem unlike lots of sponge cakes.  The fondant icing, there will be a little too much but if you use 500 you will have to roll it a little thinner than I like.  Why does that matter?  The thinner the icing the more likely it is to tear so buy enough and roll out to roughly the thickness of a £1 coin, it is much more forgiving this way. 

Ingredients
750g Chocolate fondant Icing (I like Renshaw) 
3 packets of fondant icing money (edible cake topper money) 
Chocolate handcuffs and gun 
2 tbsps Soft brown sugar 
2 tbsps bronze crunch (I like Waitrose cooks' ingredients) 
Dynamite candles 
GTA edible cake topper (with a large logo) 
1 packet of money napkins 
1 toy bullet belt 
1 elastic band 

Cake ingredients 
300g dark chocolate 
425g butter, softened 
525g light brown soft sugar 
6 eggs (room temperature) 
2½ tsp vanilla paste or extract 
210g plain flour 

Chocolate butter cream ingredients 
150g butter, softened 
300g icing sugar 
1 tsp vanilla paste or extract 
490ml double cream 
110g dark chocolate, chopped very finely 

Equipment needed 
25 or 26cm spring form cake tin 
Greaseproof or baking paper 
Glass plate or board 

Method
Day 1 
Preheat the oven to 160c.  Line the bottom and sides of your cake tin.  I unclip the tin, turn the bottom upside down so the very bottom is face upwards, butter it and cover it in greaseproof paper.  Now, tuck the greaseproof under and reassemble the cake tin, the greaseproof should now be sticking out of the sides.  Then butter and line the sides. 

Put a baking tray into the oven. 

Gently melt your chocolate, I do this in my microwave as I find that as long as you only do short bursts you have less chance of your chocolate seizing.  The first burst I do is 1 minute on full blast then stir using a butter knife.  After the initial burst I do 30 seconds at a time, stir and continue until the chocolate is totally melted.  Put to one side to cool very slightly.  You can do this over a ban Marie, just be incredibly careful not to get any water into the chocolate. 

Beat the butter and sugar in a stand mixer ideally until light and fluffy - this will take a couple of minutes.  If you don’t have a stand mixer you can do this with a hand whisk it will just take a little longer.  Now add 1 tbsp of flour and mix again for 10 seconds or so until fully incorporated.  Now add the eggs 1 at a time, fully mixing between eggs and scraping the bottom with a spatula every 2 eggs.  Should this mixture start to curdle (and believe me mine sometimes does), just add 1 tbsp flour and carry on.  Add the now cooled chocolate and the vanilla and mix.  Fold the flour now into the chocolate batter using a large slotted spoon scraping around the edge and through the middle, you want to keep this light so don't knock out any of the air. 

Pour the batter into your prepared cake tin and put on to the hot baking tray.  Cook for 50 minutes before checking.  This cake will get a crust on the outside and fully sets on cooling but if you gently tip the tin it should not have much movement, just a very slight wobble, a skewer won't come out clean, but it should not come but with wet batter on it.  If it is not done then put back in and check every 10 minutes until done.  I expect this to take close to 1 hour 10 minutes but have known it to take a little longer.  

When the cake is cooked, leave in the tin to cool completely.  This is very soft while warm and so will break if you remove it prematurely from the tin.  Once cool the crust will sink back a little and a few chunks may well come off, if that happens just be the hero and check it tastes nice, I find it is better if you taste it with the buttercream- just to be sure it tastes ok.  Remember, not all heroes wear capes.  When your cake is completely cold cover the whole cake in the tin in cling film and put to one side. 

While your cake is cooling make your buttercream.  Put your cream into a small saucepan and heat until it just starts to boil.  Put the finely chopped chocolate into a heat proof bowl and when the cream boils, tip the cream over the chocolate.  Stir once and then leave for a full minute before stirring until smooth and glossy.  Put to one side.   

When the chocolate is cool beat the butter and vanilla in a stand mixer for 2 minutes until super light and fluffy.  Slowly start to add the icing sugar with your mixer on slow at first because otherwise trust me, your kitchen will be covered in icing sugar. Once all of your icing sugar has been added increase the speed, the mix will be fairly stiff.  Stop mixing and add your now cool chocolate.  Mix on medium until fully incorporated.  Put into the fridge overnight. 

Day 2 
Take your buttercream out of the fridge and leave to one side for an hour.  Put your buttercream back into the mixer and mix until light and fluffy again. 

Take your glass board or plate and put a spoonful of buttercream on it. 

Remove the cake from the cling film and tin and place on the glass board upside down so that the crusty part is at the bottom and the top is perfectly smooth.  If you happen to have string then take the string and measure from the bottom of one side of your cake, across the middle of the top of your cake and down to the bottom of the other side.  This should give you the size of your cake for the size of the icing needed.  Dust away any crumbs. 

You now need to put the buttercream over the top and sides of the cake as this is effectively your glue to get your icing to stick nicely to the sides of your cake.  Put 2 large spoonful's of the buttercream on the top of the cake and with a palette knife ideally (but a butter knife will also work), spread the buttercream over the top of your cake keeping it as even as possible.  This does not need to be thick but does need to be even as this will affect your finished look.  Don't worry if it dribbles down the sides as you will also be covering the sides with buttercream. 

Now the top is done, you need to cover the sides.  This is the part I used to really struggle with, much easier if you know how to plaster a wall.  However, it is doable and you will get better with practice.  With your knife carefully start to paint the outside, here I would say that although you don't want to waste buttercream, if you are a little heavy handed don't worry too much because effectively what you will do is with your palette knife, scrape off the excess.  How you do this is hold you palette knife vertically against your cake and go around the edge removing any excess buttercream, scraping it into a spare bowl.  Repeat with the top of the cake.  You don't want too much buttercream because I find it makes the fondant icing too soft and sensitive.  You want just enough to stick the icing and for me, it is easier to do the excess and scrape than try to be perfect first time.   

Remove any crumbs from your work surface, clean down and thoroughly dry.  Remove any rings or bracelets you are wearing.  You need to roll out the fondant icing and moisture, crumbs and jewellery are the enemy of fondant icing.  Take cornflour and dust your work surface fairly liberally.  Cut open your fondant icing and knead the icing so it is soft.  If you have more than one packet then after cutting open the packets push the icing together before kneading.  Knead until the different packets are now merged as one icing ball.  This should only take a couple of mins.  Chocolate fondant icing is a little softer than ordinary fondant icing so do be careful. 

Redust your worksurface and your rolling pin.  I find that the fondant can stick once you start to roll it out despite the flour, so turn the icing one turn to the left every few rolls and be aware you may need to add more cornflour underneath if it starts to feel too sticky.  Roll until the icing is large enough for your cake (this is where your string comes in handy as you can measure around) and ideally the thickness of a £1 coin.  Fondant icing can be a bit of a pain and stretches and cracks fairly easily so try to handle it with care and try not to make it thinner than a £1 coin, a little thicker is ok. 

Once you are happy it is large enough and the right thickness the easiest way to move it from the board to your cake is to gently and carefully roll the icing around the rolling pin.  Before you start move your cake back to your work area close to the icing so you can move quickly.  Lightly dust cornflour over the top of your icing and smooth it over - this removes any excess - and very carefully, starting on one edge (I tend to work left to right but if you are left handed you will probably want to do this right to left), gently roll the icing around the rolling pin, wrapping it over itself.  

Move the rolling pin so the icing is above your cake and working from the edge of the cake left to right (or right to left) gently unroll the icing over your cake - this does need to be centralised so that it will cover all sides all the way to the bottom.  Once the icing is over the cake you will not be able to move it because it will stick to the buttercream. 

If you have cake smoothers you can use these to push out any air bubbles or creases otherwise just use your hands.  Firmly and carefully glide your hand or smoother over the top and then around the side.  I do sometimes find that the fondant around the top edge cracks slightly, I have no idea why but do know that if I gently hold my hot hand against it for 5-10 seconds then with my finger I can carefully smooth it and it does somewhat diminish.  I like to use my hands to push the bottom of the icing a little to ensure it is against the cake.  Then take a small knife and cut around the edge of the icing at the bottom of the cake, try not to cut it too short.  

The thing to say here is that you really do not want your fondant icing to dry out while you are working with it so from the moment you open the packets to the time you fit it to the cake, do this in one sitting rather than leaving the icing for any length of time. 

Take a tbsp or two of the sugar and put a pile at the top of the cake.  Take a tbsp or two of the bronze crunch and put over the top half of the sugar and just above.  

Make 3 piles of money, take 1 pile and roll them and secure with your elastic band.  Place on the cake. 

Take the GTA cake topper and cut out the logo.  Using some buttercream stick the logo to the front left of the cake. 

Take your dynamite candles and melt some of the wax so they stick together.  I like little groups of 3 but you can do whatever you prefer the look of and this may be determined by age.  Using buttercream stick these to the front right of the cake.  

Take one of the piles of your money and drape over the edge of the cake.  Take the 3rd pile of money and fan out and put just over the top edge of the 2nd pile.  Put your chocolate handcuffs over the money. 

Take your bullet belt and cut to size so it goes around the sides and back of your cake.  You could always put some lose bullets on the top of the cake. 

Put your money napkins to the side on the glass board/plate. 

Hey presto, one GTA cake.