Place a large saucepan over medium heat and add milk, sugar, vanilla, cinnamon and lemon zest. Stir regularly and allow to come to the boil slowly.
When the milk has just boiled turn the heat down to low and add the rice.
Continue to stir occasionally and allow the rice to cook really slowly for 40 miutes, or until the rice is tender. You can add plain milk if the infused mixture runs out before the rice is cooked.
Remove from heat and set aside in the fridge for 3 hours or until chilled.
