Preheat the oven to 350°F (180°C) and line a baking sheet with parchment paper.
Add vegan butter and white granulated sugar to your stand mixer and cream them together until smooth.
Add soy milk and vanilla extract and mix them in.
In a separate bowl sift all purpose flour and then add baking soda, salt and matcha powder and mix them together.
Add the dry ingredients in with the wet and mix it together with a spoon. Then get in there with your hands and form it into a ball of dough.
Dust your hands and a baking mat with flour and transfer the ball of dough onto the flour dusted baking mat.
Roll out the dough to around ¼ inch thickness. Dip a cookie cutter into flour (so that it doesn't stick) and cut out the cookies.
Place the cut out cookies onto a parchment lined baking tray.
Take the remaining dough, form it into a ball again, roll it out again and cut out more cookies. Repeat until your dough is finished. You should have 20-25 cookies, depending on the size of your cookie cutter (we got 23 from our batch).
Place the cookies into the oven to bake for 10 minutes. They will be very soft so just let them firm up and cool down directly on the baking tray.
When the cookies are cooled, add vegan butter, powdered sugar, soy milk and vanilla extract to your stand mixer and starting at slow speed, gradually increase speed until the frosting is smooth.
Spread the frosting onto the cooled cookies.
Place the frosted cookies into the fridge for 10 minutes for the frosting to set and then serve!