Combine ingredients in a mixing glass with ice and stir until well chilled. Strain into a rocks glass over a large ice cube. Garnish with a shiso leaf or mint.
*To Make Matcha Syrup: Add 1 part hot water, 1 part sugar and ½ part matcha tea powder in a matcha shaker and shake for 30 seconds. Transfer to sealed container. Use within 1-2 days.