Begin by pouring 4 cups of filtered water into a medium-sized pot and bring to a boil.

Remove the pot from heat and add the Thai tea mix, star anise, and crushed cardamom. Steep for 3 to 5 minutes.

Stir in sugar until dissolved, and adjust sweetness as desired.

Pour the tea mixture through a fine mesh strainer into a heatproof container to remove solids.

Allow the tea to cool at room temperature for 10-15 minutes, then chill in the refrigerator for at least 30 minutes.

Serve by filling tall glasses with ice cubes, pour the chilled tea over the ice, and add a splash of milk.