Preheat your oven to 350°F (180°C) and line a baking tray with parchment paper and set aside.

In a medium bowl, whisk together the flour, and salt.

In a stand mixer (you can also use the hand mixer for this), add in the butter and sugar and beat it at medium speed, scraping down the sides for at least 2-3 min or until the mixture is creamy.

Add in the egg and beat until everything is well incorporated.

Divide the batter equally into two bowls. In one bowl add half of the flour along with vanilla extract and mix till it forms a dough. Take the rest of the batter in another bowl. Add the rest of the flour and matcha powder and mix till it forms a dough.

Lightly cover both the dough separately with a cling wrap and shape them into rectangular shapes using a rolling pin. Keep the thickness at about ¼-inch.

Cover with plastic wrap. Refrigerate both doughs for 30 mins.

Once chilled, cut both doughs into strips of around ½ inch width using a sharp knife.

Gently beat 1 egg white and use it as glue to stick the dough strips together. Place a strip of vanilla dough, brush a little egg white on the side, attach a strip of matcha dough next to it, and then again brush the side with egg white and attach a strip of vanilla dough. Repeat the process till you have 4 strips of alternating vanilla and matcha dough.

Repeat to make a second row of dough stacked upwards, this time starting with the matcha dough first. This will give you an alternating pattern. Repeat one more time to create three different layers stacked upwards.

Wrap the stacked dough log with plastic wrap and chill for 3 hours or up to 24 hours.

Slice the chilled dough to about ½-inch thickness. Place the cookies on the prepared baking tray about 1-inch apart.

Bake for 15-16 minutes or until the edges are lightly golden. Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.