Heat about a cup of water to 140-175°F (60-80°C) in the microwave, on the stovetop, or in an electric kettle. If the water heats to boiling, allow several minutes minutes for it to cool.
Sift the matcha powder into a tall (~16-ounce) glass to ensure there are no clumps.
Add ⅛ cup of the heated water and use a bamboo matcha whisk or milk frother to mix the matcha until it is smooth and frothy.
Stir in the sugar or preferred sweetener until the sweetener has dissolved.
Add ice and gently pour the milk onto the ice to preserve the layered effect.
Slowly add the cold brew or espresso over the top. Stir before drinking to distribute the flavors (But take pictures of the pretty layers before your drink goes olive tone).