Combine the tea, water, and sugar in a small saucepan and bring to a boil. Reduce the heat and simmer for 20 minutes. Remove from the heat and strain into a small pitcher. Allow to cool completely before serving. Tea will taste very sweet, but once ice is added, it will be more balanced. Refrigerate for 1 hour.
To serve, pack tall glasses with ice and pour in the chilled tea almost to the rim. Slowly pour about 2 tablespoons of the half-and-half over the ice in each glass, making sure to create an attractive, layered look. Garnish each with a sprig of mint.
source from: vietnameseportal