Preheat oven to 150 C / Gas 2. Line two 12 hole muffin tins with paper cupcake cases.
Place the margarine, melted chocolate, sugar, milk and vanilla paste in a saucepan and stir over a low heat until smooth. Pour into a large bowl and leave for 15 minutes to cool.
Whisk in the sifted flours and cocoa until well combined. Beat in the eggs and whisk until well combined. Spoon the mixture evenly into the paper cases, filling only to half way to ensure a good rise.
Bake in the preheated oven for 30 minutes until risen and a skewer inserted into the centre comes out clean. Remove from the oven and allow to cool completely on a cooling rack before decorating, about 60 minutes.
For the frosting:
Place the chocolate and margarine in a microwave safe bowl and microwave for about 1 minute, take out and mix if not yet melted put it in again until its completely melted and combined. Careful not to burn it.
Place mixture into a large bowl and add the icing sugar, soured cream and golden syrup and whisk until all well combined.
Spread the chocolate icing over the cupcakes generously. Chop the Flake® bars into about 2.5cm (1 in) pieces and open up so that you have thin spikes and start poking them leaving space for the face. Place a pair of edible eyes at the front and a Malteser® for the nose. Serve and enjoy!
If you don't have edible eyes you can make them out using white and chocolate fondant, also the nose can be made out of the chocolate fondant.