Bring 4¼ cups of water to a boil. Pour about ¼ cup of it over 4 teaspoons of gunpowder green tea and drain it off at once, keeping the leaves.
Put the leaves in a teapot with the remaining boiling water, ½ cup of fresh mint leaves, and ¼ cup of sugar. Stir until the sugar dissolves, cover, and steep for 5 minutes.
Pour into cups from a height and garnish with more mint.
