Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4 and line a cupcake tin with black cupcake cases
Whisk the butter and sugar together in a mixing bowl until fluffy, ideally with an electric mixer using the paddle attachment
Add the eggs and vanilla extract, and mix them in
Add the buttermilk, cocoa powder, bicarbonate of soda, red food colouring and self raising flour, mix until combined
Divide the mixture between the cupcake cases
Bake for 20-25 minutes or until a skewer inserted in the centre of a cupcake comes out clean, then put them on a cooling rack to cool fully
Once fully cool, use a cupcake corer or a knife to make a hole in the centre of each cupcake
Fill each hole with the jam, you can use a small spoon or a piping bag to do this
To make the buttercream, mix the butter on it's own for a couple of minutes. This should ideally be done with an electric mixer using the paddle attachment
Add the icing sugar, milk, vanilla extract and a small amount of pink food colouring, and mix until smooth. (Remember that you only want a pale pink colour so be sparing with the pink food colouring, you can always add more but you can't take away!) If the buttercream is too stiff then you can add a little more milk
Put the buttercream in a piping bag fitted with a circular/round nozzle. Pipe a line down the centre of the cupcake, then squiggles on either side for the brain effect
Keep in an airtight container in a cool place, and eat leftovers within 3 days