My mother's best friend, Haruko had an Australian husband and therefore celebrated Christmas traditions (just like my mother). She was a great cookie baker and made batches of wonderful cookies for the holidays, and this is her recipe. The Japanese love flavoring desserts with that distinct, bitter flavor of matcha tea, and these cookies are no exception. I like them quite dark and flavorful but you can use a little less matcha for paler cookies and a more delicate flavor. Haruko's delicate, buttery cookies are inspired by Spanish polverone cookies, which can also be simply dusted with confectioners' sugar rather than decorated with icing. These are perfect with a cup of tea. —Emiko
For the cookies, beat the butter until creamy and smooth. Add the other ingredients and combine to make a smooth, soft dough. You can let it rest half an hour, wrapped in plastic, in the fridge if it is a bit too soft.
Roll on a lightly floured surface to about 1/3 inch (8 millimeters) thick. Cut out shapes with a cookie cutter and place on a baking sheet lined with baking paper.
Bake at 325° F (160° C) for 15 minutes or until they are still pale (not yet golden) but dry to the touch. Remove from the oven and let cool 5 minutes on the tray before moving to a cooling rack.
In the meantime, make the icing by mixing little by the little the egg white into the confectioners' sugar until you have a thick but smooth paste. With the back of a wooden skewer (the flat not the pointy end), decorate the cooled cookies with polka dots. Pop the cookies back in a low oven for 5 minutes to set the icing. Alternatively, you can simply dust with confectioners' sugar and serve. Store cookies in airtight container at room temperature.