The day before making the cake, pour the port into a pan with the star anise. Bring to the boil, remove from the heat and leave for a good few hours to infuse. Place the figs, dates and prunes in a large bowl with the treacle, zests, mixed spice, nutmeg and port (removing the star anise). Stir, cover and leave overnight.
The next day, butter and line the sides and base of a 23cm square, 7.5cm deep tin (do not use a loose-based tin) with baking parchment. Wrap brown paper round the tin and tie with string. Preheat the oven to 150°C/fan 130°C/300°F/gas mark 2. Put the nuts on a baking tray and cook for 10 minutes, until toasted. Cool and chop. Place a tray of hot water (large enough to hold the cake tin) in the oven.
In a food mixer, beat the butter and sugar for at least five minutes, until pale and creamy. Mix in the eggs slowly, adding 1 tbsp of flour to stop the mixture curdling. Using a large spoon, fold in the remaining flour, the salt, the fruits and their liquid, and the nuts. Fold together and tip into the tin.
Place in the water-filled tray and bake for 2 to 2 and a half hours, or until a skewer comes out almost clean with a couple of crumbs on it. If the top is browning before it is cooked, protect with foil. Cool in the tin, on a wire rack. When cold, prick all over with a skewer and sprinkle over the extra port. Wrap in baking parchment and then in foil, and leave for at least a few weeks.
A week before Christmas, bring the jam and brandy to the boil, push through a sieve and brush most of it over the cake. Decorate with dried fruits and nuts, glazing with more jam. Paint the star anise with egg white and glitter, and add (they are not for eating). Wrap the sides of the cake with baking parchment or clear film to stop it drying out. Finish with a ribbon or lengths of raffia.