In a small saucepan, combine whole milk, black tea leaves, and pure maple syrup. Heat the mixture over medium heat until it reaches a gentle simmer. Remove the saucepan from the heat and allow the mixture to come to room temperature.
Brew the espresso using your preferred method. Let the espresso cool to room temperature.
Once both the milk tea and espresso have reached room temperature, refrigerate until chilled (at least 1 hour).
When ready to serve, fill a glass with ice cubes, pour the chilled espresso over the ice, then pour the cooled milk tea into the glass over the espresso. Give it a gentle stir to combine the flavors and enjoy cold.