Prepare the Dry Ingredients: In a medium bowl, whisk together 300 g of all-purpose flour and ¼ teaspoon of salt until combined.

Cream the Butter and Sugar: Using an electric hand mixer, beat 230 g of softened unsalted butter in a large bowl until creamy. Gradually add 100 g of granulated sugar and continue to beat until pale and fluffy.

Mix in the Egg Yolk and Vanilla: Add 1 egg yolk and 1 teaspoon of vanilla extract to the creamed butter mixture. Beat on low speed until just blended.

Combine Dry and Wet Ingredients: Gradually add the reserved flour mixture to the butter mixture, beating on low speed until just combined.

Divide and Color the Dough: Divide the dough into two equal bowls. Leave one half as vanilla dough, and sift in 20 g of matcha powder to the other half.

Shape and Chill the Dough: Press each color of dough into rectangles on parchment paper, roll to about ¼ inch thick, and refrigerate for at least 1 hour.

Assemble the Dough Layers: Peel one dough sheet off the parchment paper and lay it on top of the other. Cut in half and brush the exposed edge with egg white.

Stack and Chill Again: Stack the layers to form a new block and chill in the refrigerator for an additional 15 minutes.

Cut and Layer the Strips: Cut the block into ¼ inch wide strips and brush each strip with egg white before layering alternately.

Final Chill and Preheat Oven: Refrigerate the assembled blocks until firm, then preheat your oven to 350°F (175°C).

Slice and Arrange Cookies: Slice each block into ¼ inch thick cookies and place them on the prepared baking sheet.

Bake and Cool: Bake for 12-15 minutes until the edges just start to brown and cool on the baking sheet for 5 minutes.