In a small bowl, add the matcha powder and 1 Tbsp boiling hot water. Whisk until the mixture forms a sort of paste.
Pour in the 1 cup hot water and mix well. Transfer to the fridge to cool, around 15-20 minutes.
Divide the ice between 2 tall glasses or mason jars. Pour 2/3 cup milk into each. Divide the chilled matcha into both glasses and mix to combine.