Flour mixture: In a medium bowl, add the flour. Sift in the matcha powder to break up any clumps. Add the baking powder and salt and stir to combine. Set aside.
Egg mixture: In a large mixing bowl, add the eggs and sugar. Use a whisk to mix well until the eggs are slightly pale in colour, about 3 minutes. Slowly stream the melted butter into the egg mixture while whisking constantly.
Combine flour and egg mixtures: Add the flour mixture and fold with a spatula until just combined.
Chill dough: Chill the whole bowl of cookie dough in the fridge for at least 1 hour to let it firm up.
Prep: Preheat oven to 325°F. Line a baking sheet with parchment paper. Set aside.
Prepare the sugars: Place the granulated sugar and powdered sugar in two separate shallow dishes.
Scoop dough: Use a 3-tablespoon cookie scooper to scoop the cookie dough. Release the cookie dough into the granulated sugar.
Roll in sugars: Roll the dough ball in granulated sugar first. Roll it in between your hands briefly to create a round ball and then roll it in powdered sugar until generously coated. Place the cookie dough balls on your lined baking sheet, leaving about 1-2" in between each ball.
Bake: Bake cookies for about 11 minutes or until the powdered sugar forms a cracked pattern and the cookies are puffy.
Cool: Let the cookies cool for 5 minutes on the baking sheet before transferring them to a wire rack to cool completely.