Place the chocolate in the top of a double boiler. Place over simmering water and heat until melted.
Meanwhile combine the half and half, orange zest, cinnamon stick, and brown sugar in a large saucepan. Heat over medium heat to a gentle boil, then strain.
Slowly stir the melted chocolate into the hot half and half until blended. Add the brandy, if desired.
Keep warm in the top of a double boiler over hot, not boiling, water. If the hot chocolate is overheated it becomes too thick.