Place the sultanas in a bowl and pour over the hot tea. Set aside to soak for ten minutes, then drain (discard the tea).
In a large casserole dish or rice pudding dish (roughly 30cm x 20cm/12in x 8in), mix together the milk and cream. Stir in the rice, sugar and a pinch of nutmeg. Add the vanilla pod and seeds, then stir in the soaked sultanas.
Cover the dish with a lid or sheet of aluminium foil, then 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.
To serve, spoon the rice pudding into serving bowls and serve with spoonfuls of clotted cream and jam.