Weigh or measure all the ingredients. Preheat the oven to 220C/425F/Gas 7.
Pour the lactose free milk into the ovenproof dish, then add the rice.
Prepare the blueberry by pinching out any woody stalks before adding them to the ovenproof dish.
Add the sugar and the vanilla extract. Give the mixture a stir and put on the lid. Place on a baking tray.
Cook for 20 minutes then leave to stand for at least 10 minutes with the lid on (the rice will carry on cooking). When the rice has cooled a bit, it is ready to eat.