Preheat oven to 170 deg C. Line a 8 inch square pan all sides up.

Beat the butter, sugar and vanilla till light and creamy. Add in the egg yolks one by one, until mixture incorporated, mix well.

On low speed, fold in the flour, alternating with the milk. Mix till well incorporated. Then divide the batter into two portions, adding the matcha powder into one portion and mix well.

Meringue - In a clean bowl, whisk egg whites till foamy at low speed and gradually in the sugar and beat from medium to high speed till stiff peaks. Fold half of the meringue into the plain and matcha batter in two batches till just combined with a rubber spatula.

Spoon a layer of plain batter into the pan and level it. Sift a thin layer of cocoa powder on top until evenly covered, very gently dollop a layer of matcha batter on top of the cocoa powder. Just to be patient in doing this step. Repeat with the remaining layer (do not dust cocoa powder on the top layer).

Bake for 45-50 minutes or until skewer inserted into cake comes out clean.

Leave cake to cool in pan for 15 minutes. Then remove cake and place on wire rack to cool.