Place the pan over medium-high heat and bring the tapioca to a boil. Stir and put a lid on the pan. Turn the heat lower to medium. Cook the tapioca for 20 minutes. Stir regularly. Make sure it doesn’t stick to the bottom of the pan. Add extra water if necessary.
Once the tapioca is almost tender, take the pan off the heat and drain the tapioca in a colander or sieve. Pour the cream in the same saucepan and add the caster sugar and the bag of green tea.