A classic nursery pudding for 40 people. You will need casserole dishes of equal size with a combined capacity of about 9 litres/15¾ pints.
Preheat the oven to 160C/300F/Gas 2.
Stir all of the ingredients, except the jam, together in a large bowl. pour the mixture into the baking dishes.
Cover the dishes with a lid or sheet of aluminium foil and cook in the oven for 1½ hours. Remove the lid or foil and cook for a further 20 minutes, or until the rice is tender and the top is lightly golden and has formed a skin.
Spoon the rice pudding into serving bowls and serve with spoonfuls of jam.
