Melt the butter. Set it aside for now to cool a bit.

Mix flour, matcha, baking powder, and salt together in a medium-sized mixing bowl until well blended.

In a large bowl, mix together the melted butter, sugar, eggs, and vanilla.

Stir in the dry ingredients until just combined (be careful to not overmix or the cookies won't be as tender).

Split the dough in half. Separate each half into five even pieces (for a total of ten). Roll each piece into a ball and set on a tray. Cover with plastic wrap and freeze for one hour.

Meanwhile, preheat the oven to 350°F / 180°C and line a baking tray with parchment paper. Put the granulated sugar and confectioner's sugar for rolling into two separate small bowls.

Place each frozen cookie dough ball first in the granulated sugar, rolling to coat.

Then roll them in the confectioner's sugar. Try to do this fairly quickly - as the butter in the dough comes to room temperature, it can moisten the sugar coating and lessen the crinkle cookie look.

Place the sugar-coated balls onto the prepared baking tray. Bake for fifteen minutes.

Transfer the cookies to a cooling rack to finish cooling.