Soak tapioca in cold water for 3-4 hours. Wash and drain.
In a large saucepan, combine the tapioca and water and bring to a boil. Reduce to a low heat and cook until grains swell and become transparent, stirring frequently to prevent sticking.
With a wooden spoon, stir in sugar until fully dissolved. Mix in the butter, golden syrup, lemon juice and rind.
Pour the mixture into a bowl and allow to cool before putting in the fridge to set. Serve with whipped cream.