Preheat your oven to 350°F (175°C).
In a large mixing bowl, cream together the softened butter and sugar until light and fluffy.
Add the egg and vanilla extract, mixing until well combined.
In a separate bowl, whisk together the flour, matcha powder, baking powder, and salt.
Gradually add the dry ingredients to the wet mixture, stirring until just combined.
Scoop tablespoon-sized portions of dough and roll them into balls.
Place them on a baking sheet lined with parchment paper, spacing them about 2 inches apart.
Flatten each ball slightly with the palm of your hand.
Bake for 10-12 minutes or until the edges are lightly golden.
Allow the cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.