01 - Sift the matcha powder into a mug to remove clumps. Add the hot water. Whisk vigorously with a bamboo whisk or small regular whisk until smooth and frothy.
02 - Heat the oat milk in a small saucepan over medium heat until steaming, but not boiling. Alternatively, microwave in a microwave-safe container for 45–60 seconds.
03 - Froth the oat milk using a milk frother or whisk until foamy.
04 - Pour the oat milk into the mug with matcha, holding back the foam with a spoon, then spoon the foam on top. Stir in maple syrup or sweetener, if desired.
05 - Serve immediately, optionally garnished with a sprinkle of matcha powder on top.