In order to prevent clumping, a matcha whisk* is recommended.
Place all of the ingredients into a large jar or cup (that is larger than its volume) and stir vigorously until the matcha is combined and there are little to no clumps.
It is best if allowed to sit in the fridge for at least 1 hour and served over ice.
Notes
*Matcha whisks are periodically available at iHerb. Use my code VSZ844 for a discount!