Step 1

Heat milk in a large heatproof glass measuring cup in a microwave on high until very hot but not boiling, about 45 seconds (or, heat milk in a small saucepan over medium). Using an immersion blender, carefully blend on medium speed, moving blade up and down through milk, until foamy, about 30 seconds. (Alternatively, whisk vigorously.)

Step 2

Combine matcha, sugar, and ½ cup water in an ice-filled cocktail shaker. Cover and shake vigorously until outside of shaker is very cold and latte is frothy, 30 seconds. Using a cocktail strainer or slotted spoon to hold back ice while allowing foam and small ice chips to pass through, pour into a tall, ice-filled glass. Top off with frothy milk.