First up is the sponge; preheat oven the 180°C/ 160°C Fan/Gas Mark 4. Line a 12 hole muffin tin with the cupcake cases.
Pop the flour, Baking Powder, Bicarbonate of Soda, Cocoa Powder and Sugar in a large bowl and mix together. Make a well in the centre.
In a separate bowl mix together the eggs, milk, oil and Vanilla Extract. Pour the wet mixture into the well in the centre of the dry ingredients and gently begin the fold together. Mix together until all combined and your mixture is smooth.
Divide the mixture evenly between the 12 cupcakes cases. Bake the cupcakes for 20 -25 minutes until risen and when a skewer is inserted into the centre of a cupcake it comes out clean. Leave to cool in the tin for 10 minutes and then place on a wire rack to cool completely.
Whilst your cupcakes are cooling, lets make the bat eyes; melt the White Chocolate in the microwave in in 20 second bursts, stirring between each burst until melted.
Line a tray with greaseproof paper. Pour the melted chocolate into a piping bag and cut a small hole at the end. Pipe circles of chocolate onto the greaseproof paper. Tap the tray on the side a few times to remove any air bubbles and to smooth out the chocolate and pop into the fridge to set.
Once your cupcakes are cooled, mix your buttercream in the tub and pop into a piping bag, cut a 2cm hole in the end of the piping bag and pipe a swirl of buttercream onto the top of each cupcake.
Cut each Oreo in half and pop into the top of the buttercream to look like wings. Once your chocolate has set blob a tiny bit of black colour gel into the centre, you can do this straight from the tube or use a cocktail stick and place the eyes in front of the wings in the buttercream.
Ta-dah your bat cupcakes are ready to serve and enjoy!