1.Place sugar, ginger, cinnamon, vanilla bean and juices in a large saucepan; bring to the boil. Reduce heat; simmer, uncovered, about 10 minutes or until reduced slightly.
2.Strain into a large jug. Refrigerate 6 hours or overnight.
3.To serve, pour juice mixture into glasses; top with lemon. Top up each glass with rum; stir to combine.
You will need about 7 lemons for this recipe.Note