Make the cold foam. Add the heavy cream, banana bread syrup, and whole milk to a small glass or jar and froth with a milk frother for 20-30 seconds until foamy. Set aside.
Add the water to a small microwave-safe jar or glass, and heat until boiling (30-45 seconds in the microwave). Sift the matcha into the hot water, removing any large clumps. Whisk the matcha and water together until smooth and slightly foamy. Set aside.
Add ice to a tall glass, then top with the milk and brown sugar syrup. Stir to combine. Add the matcha and stir again.
Top the matcha with your cold foam and crushed maple sugar (if using). Drink up!