Combine chocolate, orange peel, cinnamon and 3 tablespoons of milk in a saucepan and heat very gently until chocolate melts, stirring frequently
Add remaining milk and heat through gently until piping hot, stirring frequently
Whisk whipping cream until soft peaks form
Pour hot chocolate into mugs or heatproof glasses
Top with whipped cream
Sprinkle with grated chocolate and add a cinnamon stick to each one for stirring