Step 1

Mix: Use an electric mixer to cream butter, granulated sugar, and brown sugar until smooth. Mix in tea and vanilla. Then add flour and cornstarch. Mix just until a crumbly dough forms.

Step 2

Roll: Gently bring the dough together into a ball using your hands. (It'll be crumbly at first, but it'll come together after gently kneading). Roll the dough on parchment paper, until it's (1x) 8-inch (20 cm) square. (You can use a knife to trim excess dough and fill in any short spots if needed).

Step 3

Chill and preheat oven: Use the parchment paper to slide the dough onto a baking sheet. Freeze for 20 minutes. Meanwhile, preheat oven to 350°F (177°C).

Step 4

Cut and bake: Cut the chilled dough into 16 squares, about 2-inches (5 cm) each. Poke each cookie 3 times with a fork. Arrange the cookies on a parchment lined baking sheet and bake until the edges are set and pale golden, about 12 minutes.

Step 5

Sprinkle and cool: Immediately sprinkle the cookie tops with extra granulated sugar (see note 4). Let cool completely, then lift from the baking sheet and enjoy!