Put 12 unwrapped Creme Eggs in the freezer for a few hours to freeze solid
Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4, line a tin with cupcake cases
To make the sponge, mix together the butter and the caster sugar, ideally with an electric mixer, until fluffy
Add the eggs and milk, and whisk in
Whisk in the self raising flour and cocoa powder gently
Place a teaspoon of batter into each cupcake case, then add a frozen Creme Egg on top. Add about 2 more teaspoons of batter on top and around the Creme Eggs, until all the batter is used up
Bake for 20 minutes
Make the buttercream by mixing the icing sugar, butter, milk and vanilla extract together until smooth. Use an electric mixer for best results. If the buttercream is too stiff then you can add a little more milk to it
If you'd like to colour the buttercream, put half of it in a bowl and mix in some orange food colouring
Fill a piping bag fitted with a round nozzle, with the vanilla buttercream on one side and the orange coloured buttercream on the other side
When the cupcakes are fully cool pipe some buttercream on top and place a Creme Egg, cut in half, on top
Store in an airtight container in a cool place, eat leftovers within 3 days