Chop up the chocolate.
Heat the cream together with the star anise. Just before it reaches a boil, remove from the hob and leave to stand for 5 minutes.
Reheat the cream, stirring in the chopped chocolate and the sugar. Remove the star anises.
Pour the mixture into the parchment-lined baking sheet.
Cover with cling film and refrigerate for at least 24 hours.
Cut into 50-60 pieces and dust with cocoa powder.