- STEP 1
Preheat the oven to 180•c and line the base of a cake tin using grease proof paper and butter.
- STEP 2
For the chocolate mixture: Place the butter, sugar, flour, eggs and cocoa powder in a bowl and mix thoroughly until combined. Pour the mixture into the cake tin.
- STEP 3
For the plain mixture: Place the butter, sugar, flour and the egg in a bowl and mix thoroughly until combined. Pour the mixture into the cake tin with the other mixture and use a knife to stir the mixture to blend in and make a 'marble effect'.
- STEP 4
Place the cake in the middle of the oven for around 20/30 minutes. Remove the cake from the tin and place on a cooling rack.
- STEP 5
Once the cake has mostly cooled you can begin with the icing.
- STEP 6
Heat some water in a pan and place a bowl on top to melt the dark chocolate. Make sure the bowl isn't touching the water as it could cause the chocolate to burn.
- STEP 7
Once the chocolate has melted, mix the icing sugar and butter together until combined and then pour the chocolate in and continue to mix. Add milk if the mixture needs to be loser.
- STEP 8
Spread the icing on the cake equally and then sprinkle the twirl on top and dice some double decker bar and place on top.
- STEP 9
Finally - enjoy!
