Step 1: In a medium bowl, whisk together the all-purpose flour, matcha powder, baking powder, and salt until well combined and no green clumps remain.
Step 2: In a large bowl using a hand mixer or stand mixer, cream together the softened butter and 3/4 cup of granulated sugar until light and fluffy, about 3 minutes.
Step 3: Add the eggs one at a time to the butter mixture, 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 just until the flour disappears. Do not over-mix.
Step 5: Cover the dough with plastic wrap and refrigerate for at least 4 hours, or overnight, until firm.
Step 6: Preheat your oven to 325°F (165°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 slightly soft.
Step 9: Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.