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 blended. Set aside.
03 - In a large mixing bowl, beat the room-temperature butter and granulated sugar together using an electric mixer on medium speed 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 butter mixture and fold gently until just combined. Pour in the whole milk and mix lightly. Add the remaining dry ingredients and fold until the batter is smooth with no visible streaks of flour.
06 - Pour the batter into the prepared cake pan and use a spatula to smooth the surface evenly.
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 - Let the cake cool in the pan for 10 minutes, then invert onto a wire cooling rack and allow to cool completely.
09 - Whisk together the powdered sugar and matcha powder, then dust evenly over the completely cooled cake before slicing and serving.