Preheat your oven to 375 degrees and line a baking sheet with parchment paper or foil.
In a large mixing bowl, cream together vegan butter, brown sugar, oat milk, maple syrup and vanilla extract until smooth.
In a separate mixing bowl, combine matcha powder, flour and salt and stir until the green matcha powder is evenly distributed throughout.
Add the dry ingredients to the wet ingredients and stir until the dough reaches a consistency like a thick frosting.
Use a 1 ½ inch scoop or melon baller to scoop out about 20 cookies onto the baking sheet (these cookies do not expand or spread much).
Sprinkle the cookies with powdered sugar, then place in the oven for 10 minutes or until the tops begin to crack slightly.
Remove from oven, cool, and sprinkle with additional powdered sugar. Enjoy!