Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4, and line a cupcake tin with cupcake cases
To make the sponge, mix together the butter and sugar, ideally using an electric mixer
Add the eggs and vanilla extract and whisk well
Then gently whisk in the self raising flour
Divide the mixture between the 12 cupcake cases
Bake them for 20-25 minutes or until they are golden brown and a skewer inserted in the centre of the cupcakes comes out clean. Remove from the tin and leave to cool completely
Use a cupcake corer or a knife to make a hole in the middle of each cupcake
Fill the holes with the caramel sauce. You can do this using a spoon or put the sauce into a small piping bag, snip the end off and pipe it in
Make the buttercream by mixing together the butter, cocoa powder, milk and icing sugar, then add the melted chocolate, and mix until smooth. You can add more milk if required. For best results, use an electric mixer
Pipe the buttercream onto each cupcake using a piping bag fitted with your chosen nozzle. Or spread on with a spoon
Drizzle over the caramel, you can do this using a spoon or put the sauce into a small piping bag, snip the end off and pipe a drizzle over
Press a shortbread biscuit on top of each cupcake and add some sprinkles. Please note, the biscuits will go soft the longer they are in the buttercream because of the moisture, so add them as close to serving as possible
Store in an airtight container in a cool place, eat leftovers within 3 days