1.Heat milk in a large heavy-based saucepan until almost boiling. Remove from heat; stir in tea, spices and ginger until combined. Stand for 15 minutes. Pour through a sieve; discard solids.
2.Return strained milk to pan, stir in cream; bring almost to the boil. Meanwhile, whisk egg yolks and sugar in a medium bowl until pale. Gradually whisk hot milk mixture into egg yolk mixture until combined. Return mixture to pan; stir continuously over low heat until custard thickens enough to coat the back of a spoon (do not allow to boil).
3.Pour custard into a medium stainless steel bowl, place bowl over a second larger bowl filled with ice; whisk custard for a few minutes to cool slightly. Cover surface with plastic wrap; refrigerate until chilled.
4.Churn chilled custard in an ice-cream machine, following manufacturer’s directions. Five minutes before end of churning, add biscuits, nuts and glacé ginger; churn a further 5 minutes or until incorporated.
5.Pour ice-cream into a clean 1 litre (4 cup) cardboard milk carton; seal top. Freeze, standing carton upright, for 6 hours or overnight.
6.Make fig and whole spice syrup. Place ingredients, except juice, in a small heavy-based saucepan over low heat; stir for 1 minute until sugar dissolves. Bring to the boil. Reduce heat; simmer for 12 minutes or until figs have softened and syrup thickened slightly. Cool, then stir in juice. Cut half the figs in half.
7.To serve, remove parfait from freezer and tear away cardboard milk carton. Place on a platter with a lip; spoon over fig and whole spice syrup.
To crush ginger nuts, place in a metal or plastic bowl and use the end of a rolling pin to crush them; sift to remove any fine crumbs. Avoid eating whole spices as these are left in the syrup as a garnish only, the figs however will be delicious. Parfait can be made a day ahead. You can use an empty 1 litre cardboard milk carton or a 1 litre (4-cup) terrine tin to mould the parfait in.