In a large mixing bowl, whisk together 2 cups of all-purpose flour, 1 teaspoon of baking powder, and ½ teaspoon of salt until evenly combined. Set aside.

In a separate bowl, beat 1 cup of unsalted butter until creamy, then add 1 cup of powdered sugar and ½ cup of granulated sugar, mixing until fluffy. Incorporate 1 egg, 1 egg yolk, and 1 teaspoon of vanilla extract.

Gently fold the dry ingredients into the creamed butter mixture until a thick dough forms, about 1-2 minutes. Don't overmix.

Divide the dough in half, wrapping one half in plastic wrap and leaving it plain. Add matcha to the other half and mix well.

Wrap both halves in plastic wrap and refrigerate for 1 hour.

Dust your work surface with flour. Roll out both doughs to ¼ inch thick and cut into equal strips around ½ inch wide.

Whisk together the reserved egg white with 1 teaspoon of water until frothy for the egg wash.

On a baking sheet lined with parchment paper, alternate strips of the two dough flavors, applying egg wash between pieces.

Refrigerate the formed block of dough for an additional 2 hours.

Preheat your oven to 350°F (177°C) and line two baking sheets with parchment paper.

Slice the chilled block into ½ inch cookies and place them on the prepared baking sheets. Bake for 13-14 minutes until lightly browned.

Let the cookies cool on the baking sheets for about 5 minutes before transferring to a wire rack to cool completely.