Preheat your oven to 350°F. Line a baking sheet with parchment paper or lightly grease it.
In a medium-sized bowl, whisk together the flour, matcha powder, baking powder, baking soda, and salt until well combined. Set aside.
In a large bowl or using a stand mixer, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy, about 2-3 minutes
Beat in the egg and vanilla extract until well combined.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix.
Gently fold in the white chocolate chips until evenly distributed throughout the cookie dough.
Using a spoon or cookie scoop, scoop out about 1 tablespoon of dough at a time and roll it into balls. Place the dough balls onto the prepared baking sheet, spacing them about 2 inches apart.
Bake the cookies in the preheated oven for 10-12 minutes, or until the edges are set.