Use either 12 mini bundt cake moulds or a 12 cupcake tin lined with paper cases.
Preheat the oven to 160°C / 325°F / Gas mark 3.
In a large bowl, cream the butter and sugar until light and fluffy, then add the eggs and beat in followed by the flour and cocoa.
Mix until well combines then add the chopped creme egg, vanilla and a little milk to moisten and stir.
Spoon the batter into the moulds or cases, press down and even out with the back of a small spoon or butter knife.
Bake for 20-25 minutes until risen and a skewer inserted comes out clean.
Set aside to cool.
Make the topping by gently melting the chocolate either by placing a bowl in a pot of over barely simmering water or in the microwave.
Add the cocoa powder and mix thoroughly.
Slice the risen bits off the base of the bundt cakes so they have a thick and flat base, then fill the holes with the chocolate sauce so that it dribbles down the side.
Grate some chocolate over the top and decorate with a mini creme egg on each one.