Put the dried fruit in a large bowl with the alcohol, orange zest and juice. Set aside overnight to macerate.
Grease a 1.2 litre ceramic pudding bowl (see notes) and line the base with a small circle of silicone baking paper.
Add all the remaining ingredients to the bowl of soaked fruit and stir until well combined. Firmly pack the mixture into the pudding bowl, then fold a pleat into a piece of silicone baking paper and use this to cover the bowl (the pleat gives room for the pudding to expand in the oven). Follow the baking paper with a piece of pleated foil. If you want to be traditional, you can tie a length of kitchen twine around the lip of the bowl, but tightly scrunching the foil will be enough.
Put the covered pudding into your steam oven and set the oven to 212⁰F/100⁰C (steam only, humidity 100%). Cook for 6 hours – if your oven is not plumbed you’ll very likely need to top up the water tank at least once during this time (my tank lasts for over 3 hours if I don’t open the oven at all so I only have to do this once).
When the pudding is cooked, let it cool to warm, then transfer to the fridge, still covered, and store for up to 4 weeks (any longer than this and I’d recommend putting it in the freezer, it minimises potential odours/flavour contamination from other things in your fridge).
When you’re ready to serve the pudding, repeat the steaming process for 1 ½ hours to heat it through, then turn out and serve in wedges topped with ice cream and/or custard.