In a medium-sized pot, place 1/2 of the sugar, the tea and spices (spice amounts may be adjusted to your taste). Add the milk and stir well. Boil gently for about 5 minutes, or until the liquid is reduced minimally.
While the tea is warming, whisk together egg yolks, remaining sugar, and pinch of salt.
Pour the chai mixture slowly through a seive into the eggs, whisking vigorously (otherwise the eggs will curdle).
Return the mixture to the pot (after removing chai sediment). Heat the custard, stirring gently, until about 170 degrees F. Monitor carefully, as the eggs will scramble if too hot!
Place pan in an ice-bath to cool quickly, then cool in the refridgerator for about an hour.
Transfer to ice-cream maker and freeze according to directions.
If using, stir in chocolate chips near the end of the freezing process.