Preheat oven to 350F.
Sift together flour, baking powder and salt; set aside (if you have a stand mixer, you can do the sifting while the butter and sugar are beating).
Put butter and sugar in the bowl of an electric mixer fitted with the paddle attachment. Mix on medium speed until pale and fluffy, about 3 minutes. Mix in eggs. (You can use a hand mixer with the regular two beaters if that's what you've got.)
Reduce speed to low; gradually mix in flour mixture and 4 Tablespoons genmai cha. Cover dough with plastic wrap and refrigerate for at least an hour and up to overnight to let the tea flavor steep in the dough.
Shape dough into 36 (1-inch) balls. Space 2 inches apart on baking sheets lined with parchment paper (or a silicone baking sheet) and sprinkle the tops with a pinch of genmai cha. (You can also just lightly butter and flour a cookie sheet first.)
Enjoy! :)
