In a large mixing bowl, whisk together 2 cups of all-purpose flour, 1 teaspoon of baking soda, ½ teaspoon of salt, 1 tablespoon of cornstarch, and 2 tablespoons of matcha powder until fully combined.

In another bowl, beat 1.5 sticks of room temperature unsalted butter with ¾ cup of white sugar and ½ cup of light brown sugar until pale and fluffy.

Add 1 large egg, 1 egg yolk, and 1 teaspoon of vanilla extract to the creamed mixture. Beat until well combined.

Gradually add the dry mixture to the wet ingredients, mixing gently until a cohesive dough forms. Fold in 1 to 1½ cups of white chocolate chips.

Cover the dough with plastic wrap and let it rest in the refrigerator for at least 20 minutes.

Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper. Portion out ¼ to ⅓ cup of dough and space them 2 inches apart.

Bake for 11-12 minutes, looking for golden edges while the centers remain soft.

Let the cookies sit on the baking sheet for about 10 minutes to firm up, then transfer to a wire rack to cool completely.