The ganache needs to be made first as it needs to cool and set overnight before being applied to the cake. In a heavy based saucepan heat the cream until it is at boiling point.
Put half the chocolate in a large bowl and pour over the hot cream. Whisk with a hand whisk until mixture is smooth. Add the remaining chocolate a handful at a time and keep whisking to melt the lumps. Allow to cool completely and set overnight.
Line the bottom of two 20cm cake tins with baking parchment. Pre heat oven to 180°c.
First make the vanilla sponge. Beat the butter and sugar together until fluffy then beat in the eggs one at a time until well combined. Before adding the third egg add a spoonful of the flour into the mix to help stop the mixture curdling.
Stir in the vanilla extract then fold in the flour. It needs to be of dropping consistency (in other words it drops off the spoon easily). If not, add a small amount of milk to help loosen the batter. Split the mixture equally into two bowls.
Now make the chocolate sponge. Beat the butter and sugar together until fluffy then beat in the eggs one at a time until well combined. Before adding the third egg add a spoonful of the flour into the mix to help stop the mixture curdling.
Stir in the vanilla extract then fold in the flour and cocoa. Add milk if needed to get it to dropping consistency. Share the mixture equally between another two bowls.
Take one bowl of the vanilla cake mix and one of the chocolate mixture. Blob the mixture one spoon at a time into one of the cake tins then swirl the mixture a small amount with a skewer. Repeat with the other mixture in the remaining cake tin.
Bake for around 40 minutes until the cakes have risen and a skewer comes of out the cakes clean.
Let the cake for rest for a few minutes before turning it out of the tin and removing the baking paper. Allow to cool on a wire rack.
Blast the ganache for 10 seconds or so in the microwave to make it easier to spread. Don’t overheat the ganache or will burn.
Put a small amount of the ganache on the 8 inch cake board and stick one of the cakes to the board. If need be trim the top of the cake to make it flat. Brush with some of the syrup to help keep cake moist.
Spread some of the ganache on the top of the bottom cake and place the next cake on top. Again trim the cake to make it flat and brush with syrup.
With a pallet knife begin to build up the ganache on the side of the cake until it is in line with the edge of the board. Then spread the ganache onto the top of the cake. Let it set overnight.
If you want a defined edge on the ganache once the cake has set overnight take a long pallet knife, dip in boiling water and glide across the cake to smooth the ganache. Allow the cake to set again overnight.
Make a paste of royal icing and put a large blob of this in the center of the 10 inch cake board then place the cake on the smaller board in the middle.
Knead the sugarpaste until it is soft then roll out on a piece of baking parchment or worksurface lightly dusted with icing sugar until big enough to cover cake. Use the palm of your hand to buff the icing and give it a shine.
Brush the cake with some of the remaining syrup then transfer the sugarpaste across to the cake. Smooth the icing on the top of the cake then work your way down the sides gently working the icing down to stop creases. Carry the icing on along the board to cover it then trim with a sharp knife. Buff the icing again with your hand and/or plastic smoother.
Adorn the cake with sugarpaste decoration. Use gin or vodka to stick the decorations on as it is sticker and less likely to stain the sugarpaste.