In a medium saucepan, bring 4 cups of filtered water to a rolling boil over medium-high heat.

Once the water has boiled, remove the saucepan from heat and add 4 tablespoons of Thai tea leaves. Stir gently, cover, and steep for 15-20 minutes.

After steeping, strain the tea using a fine mesh sieve into a pitcher. While still hot, stir in sugar to taste until dissolved.

Allow the sweetened tea to cool to room temperature, about 15-20 minutes.

While the tea cools, fill tall glasses with ice cubes.

Pour the cooled Thai tea over the ice in each glass, filling them until they're about three-quarters full.

Gently pour evaporated or coconut milk over the tea in each glass.

If desired, stir the tea lightly before serving and garnish with star anise or a sprinkle of spices.