The oat milk gives the latte a creamy texture, while the matcha powder provides a gentle boost of energy and gives the drink its signature pretty green color.
Add hot water, sugar, vanilla, and matcha powder together in a small bowl and whisk until the ingredients are well combined and the sugar has dissolved.
If serving as an iced latte, add your desired amount of ice to a tall glass and pour in the chilled oat milk, followed by the matcha mixture. Stir to combine and serve.