Deseed the vanilla pod
Preheat the oven to gas 3, 170°C, fan 150°C. Grease a 2.5-3ltr ovenproof dish with a little butter. Use a small, sharp knife to halve the vanilla pod lengthways, then scrape out the seeds.
Scraping the seeds from the pod means that they can disperse into the pudding, giving maximum flavour. For a taste twist, try a cinnamon stick, or pared orange or lemon zest.