Step 1: In a medium bowl, whisk together the flour, matcha powder, baking powder, and salt until well combined and no green clumps remain.
Step 2: In a large bowl, cream together the softened butter and 1 cup of granulated sugar until the mixture is light and fluffy.
Step 3: Add the eggs one at a time, beating well after each addition, then stir in the vanilla extract.
Step 4: Gradually add the dry ingredients to the wet ingredients, mixing on low speed until a soft dough forms. Do not overmix.
Step 5: Cover the bowl with plastic wrap and refrigerate for at least 4 hours, or ideally overnight, to allow the dough to firm up.
Step 6: Preheat your oven to 350°F (175°C) and line two large baking sheets with parchment paper.
Step 7: Scoop tablespoon-sized portions of dough and roll them into 1-inch balls.
Step 8: Roll each ball first in the extra granulated sugar, then coat heavily in the powdered sugar.
Step 9: Place the balls on the prepared baking sheets about 2 inches apart.
Step 10: Bake for 10-12 minutes. The cookies will crack and look slightly soft in the center. Cool on the pan for 5 minutes before transferring to a wire rack.