Just fill the bottom of a large soup pot with water. Place something waterproof and crack proof in the base so that the pudding is elevated just above the water. I used an inverted steel pie tin.
Grease your pudding bowl liberally. You can line the circular base of the pudding bowl as an insurance policy, if you like.
Mix together all the ingredients for the pudding and stir thoroughly to combine. Pour the mixture into the pudding tin. You can place a piece of baking paper on the bottom of the pudding too – this will stop any rogue water getting in but also result in a smooth base.
Layer two pieces of foil over the pudding and secure tightly with string. Place the pudding on the little island you've created and pop the lid on.
Turn the heat to a low-medium, and set the timer for 2 hours.
Once the two hours are up, open the pudding carefully (so you can continue to cook if necessary but also so you don't get a steam burn.) If there is a bit of squishiness when you press the centre of pudding, cook in additional 15 minute increments until the centre feels completely firm.
Allow to cool a little before gently running a knife around the edge (if necessary) and inverting onto a plate. Serve with lactose free custard or ice cream and some berries.