Preheat the oven to 180°C (160°C Fan, Gas Mark 4). Grease and line an 18cm (7inch) square tin and a 900g (2lb) loaf tin. For the bat cake, put 100g (3 ½ oz) margarine, 100g (3 ½ oz) caster sugar and 2 eggs in a mixing bowl. Sieve 100g (3 ½ oz) flour, the Cocoa Powder and 1tsp Baking Powder on top. Carefully mix all the ingredients together until well blended.
Spoon into the prepared square tin, smooth the top and bake for about 25 minutes until lightly risen and firm to the touch. Leave to cool for 5 minutes then turn on to a wire rack to cool completely.
Put the chocolate cake on a board and using a bat cutter approx. 10 x 4.5cm stamp out 6 bats – you may need to cut out the shapes on the diagonal in order to make 6 bats. Make sure your bat cutter will fit inside the prepared loaf tin. Keep the chocolate cake trimmings for cake pops or truffles. Set aside.
Use the remaining cake ingredients to make up another mixture as above, and flavour with Orange Extract.
Spoon one third of the mixture into the prepared loaf tin, and spread to cover the base. Arrange the sponge bats, upright, down the length of the tin – they should fit snugly together.
Carefully spoon the remaining cake mixture on top of the bats, smooth the top then gently tap the tin on the work surface to help the mixture settle round the bats and to prevent it bubbling out of the tin during cooking. Make sure the bats are well covered in cake mixture to help create the surprise.
Bake in the oven for 45-50 minutes until lightly risen, golden brown and firm to the touch. Leave to cool for 10 minutes before removing from the tin and cooling on a wire rack.
To decorate, smooth the Chocolate buttercream over the top of the loaf cake using a palette knife. Knead the Black fondant icing on a surface lightly dusted with icing sugar. Once soft and pliable roll to a thickness of ½ cm and cut out bat shapes. Push the floristry wire into the centre of each fondant bat and leave to firm up on a sheet of greaseproof – this should take 2 hours to set but ideally leave overnight.
Just before serving place the fondant bats on wire into the top of cake, you can curl some of the wire around your finger to create spiral effects. Your cake is now ready to be cut into and reveal your batty surprise!