Bring the water to a simmer in a small saucepan. Add the black tea and simmer gently for 5 minutes.
Strain the tea through a fine strainer or cloth tea sock into a heatproof pitcher. For a stronger drink, pour the tea through the leaves a second time.
Add Milk and Serve:
Return the strained tea to the saucepan over low heat. Stir in the evaporated milk and condensed milk and warm until steaming, but do not boil.
Pour into glasses and serve hot, or pour over ice for iced Hong Kong-style milk tea.
Notes
Evaporated milk gives the drink its classic richness without making it overly heavy.
Straining the tea more than once creates a smooth, concentrated cafe-style texture.
Use extra ice for the iced version because the drink is brewed strong.