Begin by preheating your oven to 160°C. Grease a pudding basin or ovenproof bowl and line the base with parchment paper.
In a mixing bowl, cream the butter and brown sugar together until light and fluffy. Beat in the eggs one at a time, then add the vanilla extract, orange zest, and brandy, mixing well.
In a separate bowl, sift together the flour, baking powder, mixed spice, and salt. Gradually fold the dry ingredients into the wet mixture, then stir in the dried fruit and nuts until evenly combined.
Spoon the mixture into the prepared pudding basin and cover tightly with foil. Place the basin in a larger pot with an inch or two of simmering water at the base. Steam the pudding gently for 2–2½ hours, checking the water occasionally and topping up if needed.
Remove the pudding from the water and allow it to cool slightly before serving. Traditionally, it’s served with custard, cream, or brandy butter, and can be reheated before serving if desired.