Preheat the oven to 350* F and line a baking sheet with parchment paper.
In a bowl, whisk together the flour, baking soda, salt, cornstarch, and matcha powder.
In a separate bowl, beat together the butter and sugars until light and fluffy.
Add the egg and vanilla extract to the butter/sugar mixture and beat until smooth.
Combine the dry ingredients with the wet ingredients until a dough forms. Add the white chocolate chips and mix until just combined.
Portion into ¼ cup sized balls on the baking sheet and bake in the preheated oven for 11 minutes or until edges are golden and center is still soft.
Allow the cookies to rest for about 10 minutes or until firm and cool. Use the black icing to dot onto the white chocolate chips to make extra spooky eyeballs! Enjoy!
