Infuse 2 teaspoons Thai iced tea overnight in 2 ounces vodka. (Or, make a larger batch by adding 6 tablespoons of loose tea per liter of vodka). Strain out the tea leaves, then pour 2 ounces tea and 1 tablespoon simple syrup in a shaker, along with 2 ounces water if a less potent drink is preferred.
Pour over ice, and top with 2 ounces evaporated milk.
*Can be found at Asian supermarkets or online