Preheat oven to 325° F. Line a baking sheet with parchment paper or a silpat mat (or grease the baking sheet). In a medium bowl, sift flour, matcha, baking soda, and salt.
In a large separate bowl, put brown sugar, white sugar, and butter and beat until creamed. Add in vanilla extract, egg, and egg yolk. Mix until creamy.
Mix the flour mixture into the butter mixture until just blended (do not over mix). Add chocolate chips and fold into the dough.
If you would like the flavors to meld more, put the dough into plastic wrap and refrigerate for several hours. You can skip this step if you prefer but it does make a difference in texture and taste.
Form dough into small balls (about 1 tbsp or small golf ball sized - if it's refrigerated they will hold their shape into balls but if you skipped that step they won't be ball shaped really). Place onto prepped baking sheet about 2-3 inches apart.
Bake 8-10 minutes, depending on your oven, or until edges are lightly browned. Let cookies cool on the baking sheet for a couple of minutes before transferring it to a rack to cool completely. Then enjoy!