Pre-heat your oven to 140C Fan/160C/325F/Gas Mark 3, and line a cupcake tin with cupcake cases
For the cupcake sponge, mix together the butter (or baking spread) and caster sugar, ideally using an electric mixer, for 5 minutes until smooth and fluffy
Add the eggs and milk, and mix them in well
Gently whisk, or fold in, the self raising flour, cocoa powder and baking powder
Divide the mixture between the cupcake cases, and bake them for 25-30 minutes or until a thin skewer inserted in the centre of the cupcakes comes out clean. Put them on a rack to cool completely
When they are cool use a cupcake corer or a knife to remove a section from the middle of each cupcake. Fill the holes with the salted 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
For the buttercream, mix the softened butter on it's own for a few minutes. Then add the icing sugar, caramel sauce and milk, and mix until smooth. You can do this by hand, but an electric hand whisk or stand mixer with paddle attachment will provide the best results. If the buttercream is too stiff, you can add a little more milk
Pipe the buttercream onto each cupcake using a piping bag fitted with a nozzle of your choice (I used an Ateco 829) or spread on with a spoon
Drizzle caramel sauce over the buttercream, and top with the halves of Caramel Egg
Store in an airtight container in a cool place, eat leftovers within 3 days