Soak the fruit in the sherry overnight.
Mix the sugar, spice, flour, baking powder, salt, breadcrumbs, zest, suet and nuts in a large bowl.
In a jug, whisk together the soya milk, soya yoghurt, black treacle and stout. Pour this into the dry ingredients and mix well until fully combined.
Grease a 1.1 litre (2 pint) pudding bowl generously, and tip in the pudding mixture - it should come about three quarters of the way up the basin - don't overfill it or this will cause problems later on! Cut out a circle of baking parchment or greaseproof paper and place this over the pudding mixture.
Either put the lid on your pudding basin, or else wrap it in two layers of foil, pleating it at the top to allow for expansion and steam. Seal it tightly so that water can't get in to your pudding during steaming. Steam the pudding for 4 hours - either in a steamer, or place a jam jar lid in the bottom of a saucepan, then fill the saucepan with water until it is two thirds up the side of the pudding basin. Keep checking water levels as it cooks, you don't want it to boil dry.
When the pudding is cooked, leave it to cool, then wrap tightly in foil and store in a cool place until Christmas. For a boozy pudding, feed it regularly with brandy or sherry.
Steam for 1.5 hours, as described above.
To serve alight, warm 3-4 tbsp brandy in a small jug the microwave. Just before bringing to the table, pour the brandy over the pudding then light with a match.