How to Make It
Place butter and sugar in bowl of a stand mixer fitted with paddle attachment; beat on
medium speed until creamy, 3 to 4 minutes. With mixer running on low speed, add tea,
zest, and vanilla; beat until combined, about 30 seconds. Whisk together flour, salt, and
baking powder in a separate bowl. With mixer running on low speed, add flour mixture to
butter mixture in 3 batches. Continue beating until just smooth, 10 to 15 seconds after last
addition, stopping to scrape down sides as needed.
Divide dough in half. Shape each half into a 7-inch-long log. Wrap each log in plastic wrap; refrigerate until very firm, at least 2 hours and up to 4 days.
Preheat oven to 350°F. Unwrap 1 log, and slice into 21 (1/3-inch-thick) slices. Arrange cookies, spaced 1/2 inch apart, on a baking sheet. Bake until edges are just browned, 12 to 14 minutes. Cool on a wire rack 15 minutes. Repeat process with second log.