Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4, and line a cupcake tin with cupcake cases
For the cupcake sponge, mix together the butter and caster sugar, ideally using an electric mixer, until smooth and fluffy
Add the eggs and orange extract and whisk them in well
Then gently whisk in the self raising flour, baking powder and cocoa powder
Divide the mixture between the cupcakes cases, and bake them for 20-25 minutes or until a skewer inserted in the centre of the cupcakes comes out clean. Put them on a rack to cool completely
Make the buttercream by mixing together the butter, cocoa powder and icing sugar, then add the orange extract and milk, and mix until smooth. You can do this by hand, but an electric whisk are stand mixer with paddle attachment will provide the best results. If the buttercream is too stiff, you can add a little more milk
Spread or pipe the buttercream on top of the cupcakes
Decorate with the Terry's chocolate orange segments and orange sprinkles
Store in an airtight container in a cool place and eat within 3 days