Pre-heat your oven to 160C Fan/350F/Gas Mark 4 and line a cupcake tin with paper cases
To make the cupcakes, mix together the butter and caster sugar until smooth, ideally using a electric mixer
Add the eggs and milk, and whisk in
Add the self raising flour, Galaxy Hot Chocolate Powder and baking powder and whisk in gently
Divide the mixture between the cupcakes cases, and bake them for 20-25 minutes or until a skewer inserted comes out clean. Put them on a rack to cool completely
To make the buttercream, mix together the butter and icing sugar idelly with an electric whisk, when it starts to come together, add the milk and Galaxy spread and mix until smooth. 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. Or spread on with a spoon
Top with pieces of the Galaxy chocolate bar
Store in an airtight container in a cool place, eat leftovers within 3 days