First, place the figs and brown sugar in a medium-sized saucepan and add 10 fl oz (275 ml) water.
Bring this up to simmering point and simmer gently with a lid on for about 5 minutes, then uncover and continue to simmer for a further 5 minutes or until the figs are plump and tender. Now remove from the heat, replace the lid and leave them until they're completely cold.
The next stage is to purée the figs, so drain off the cooking liquid, snip off and discard the tops of the figs, then place them either in a liquidiser or a food processor, along with the milk, and blend them until they have become smooth and uniform. Now press the mixture through a sieve to extract any tough, resistant pieces of skin.
Next, make the custard by whisking the egg yolks, custard powder, caster sugar and vanilla extract thoroughly together. Now bring the milk and fig mixture up to the boil, then pour it on to the egg yolk mixture. Return the whole lot to the saucepan and bring it back to the boil gently, still stirring with a whisk to keep it smooth. If it looks like curdling, don't worry: just whisk it together again as it cools (the custard powder is there to keep it stabilised). Now let the custard cool before combining it with the brandy and the double cream (lightly whipped until it just holds its shape).
Place the mixture in an ice cream maker and churn according to the maker's instructions – you will probably have to do this in two batches. If you don't have an ice-cream maker then whip it by hand as soon as it freezes. Pack the ice cream into a storage container and store in the freezer until ready to use. Before serving remove it to the fridge for 30 minutes to soften.