Cream together the butter and sugar in large mixing bowl.

Add the eggs and vanilla. Mix.

Add the flour, baking powder and salt, and mix well.

Take out about half the dough, ball it up. wrap in plastic wrap and put aside.

Add the matcha powder to dough remaining in bowl, and mix until color is thoroughly blended.

Ball this dough up, and wrap, as well. Refrigerate the dough for about 15-20 minutes, just enough to stiffen it a little.

Divide each ball in half then roll out into long rectangle. Tuck edges in as they crack, helping the dough to obtaining a relatively uniform shape.

Lay one white over one green and vice versa.

Trim off edges. And gently roll like a cigar (plastic wrap can be helpful in doing this). You will end out with two long dough logs.

Place the dough logs in refrigerator for at least an hour.

Preheat oven to 325 degrees.

Take out the dough, and slice off ¼ inch cookies. Place the cookies on parchment lined baking sheets.

Bake for 12-14 minutes. Pay close attention after about 10 minutes, we don't want these cookies to brown at all on tops.

Place cookies on racks.to cool.