In large heatproof mug, place 2 tea bags and boiling water. Set aside so tea can steep for
10 minutes. Discard tea bags and let tea cool.
In 2 tumbler glasses, divide julienned shiso and lemon and lime juices equally. With spoon, bruise shiso lightly. Fill each tumbler with ice, divide green tea and gin (if using) evenly between glasses, and stir lightly to combine. Garnish with an extra shiso leaf and serve.
Per serving (including gin): 155 calories; 0 g protein; 0 g total fat (0 g sat. fat); 3 g total carbohydrates (1 g sugars, 0 g fiber); 5 mg sodium