01 - Preheat oven to 350°F. Grease an 8-inch round cake pan and line the bottom with parchment paper.
02 - In a medium bowl, whisk together the all-purpose flour, matcha powder, baking powder, and salt until evenly distributed. Set aside.
03 - In a large mixing bowl, beat the room-temperature butter and granulated sugar together using an electric mixer until pale, light, and fluffy, approximately 3 minutes.
04 - Add the eggs one at a time, beating well after each addition until fully incorporated. Stir in the vanilla extract.
05 - Add half of the dry ingredient mixture to the wet mixture and fold gently until just incorporated. Pour in the whole milk and mix lightly. Fold in the remaining dry ingredients until the batter is smooth and no streaks of flour remain. Do not overmix.
06 - Pour the batter into the prepared 8-inch cake pan and smooth the surface evenly with a spatula.
07 - Bake on the center rack for 28 to 32 minutes, or until a toothpick inserted into the center of the cake comes out clean.
08 - Allow the cake to cool in the pan for 10 minutes, then invert onto a wire cooling rack to cool completely.
09 - Whisk together the powdered sugar and matcha powder, then dust evenly over the fully cooled cake before serving.