Add water to a saucepan, and place over medium-high heat.
Crush cardamom pods with mortar and pestle or flat of a knife. Add cardamom, star anise, cloves, cinnamon, and tamarind to the saucepan, and bring to a simmer. Reduce heat to low and simmer for 5 minutes.
Add tea bags; stir to combine. As soon as water returns to a simmer, turn off heat, and steep for 5 minutes.
Stir in sugar, and let stand 5 minutes more. Strain into a container, squeezing tea bags thoroughly. Wrap container and refrigerate until very cold, about 1 hour.
To serve, fill a tall glass with ice. Pour in tea; top with a generous splash of coconut milk.
