01 - Preheat the oven to 350°F. Line an 8x8-inch baking pan with parchment paper, leaving some overhang for easy removal.
02 - In a medium bowl, whisk together the flour, matcha powder, baking powder, and salt until evenly blended.
03 - In a large bowl, whisk the melted butter and sugar until well combined. Add the eggs one at a time, whisking after each addition, then stir in the vanilla extract.
04 - Gradually fold the dry ingredients into the wet mixture until just combined. Do not overmix to maintain a tender texture.
05 - Gently fold in the chopped white chocolate until evenly distributed throughout the batter.
06 - Pour the batter into the prepared pan and spread evenly. Bake for 22–25 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs.
07 - Allow to cool completely in the pan before lifting out using the parchment overhang and cutting into squares.