Step 1: In a medium bowl, whisk together the flour, matcha powder, baking powder, and salt until well combined and no lumps of matcha remain.
Step 2: In a large bowl, cream the softened butter and 1 cup of granulated sugar together with an electric mixer until light and fluffy, about 3 minutes.
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 just combined. Do not overmix.
Step 5: Cover the dough and refrigerate for at least 2 hours (or 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 about 1 tablespoon of dough and roll into a 1-inch ball. Roll the ball first in the extra granulated sugar, then generously in the powdered sugar.
Step 8: Place the balls on the prepared baking sheets, spaced 2 inches apart. Bake for 10-12 minutes until the edges are set but the centers are still soft.
Step 9: Let the cookies cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.