Cream the butter until smooth.

Add powdered sugar and egg to the butter and mix lightly using a hand mixer.

Sift the cake flour into the mixture and combine thoroughly.

Divide the dough into three portions: one plain, one with matcha powder, and one with cocoa powder.

Cover the dough lightly with plastic wrap and refrigerate for 30 minutes.

Shape the dough into desired forms and bake at 160°C (320°F) for 20 minutes. Optionally, create marble patterns by mixing doughs.