1. Preheat the oven to 350°F (180°C) with a rack set in the middle position.
2. Line 2 cookie sheets with parchment paper.
3. Set aside.

Make the cookies:

1. In the mixing bowl of the stand mixer fitted with the flat beater attachment, beat butter and 1½ cups (300 grams) granulated sugar on medium-high (7–8) speed until light and fluffy, 2–3 minutes.
2. Scrape down the sides of the bowl, add egg, and beat until blended.
3. In a medium bowl, stir together flour, 2 tablespoons (12 grams) tea, zest, baking powder, and salt until blended.
4. Reduce the mixer speed to medium-low (3–4) and add the flour mixture, ½ cup (60 grams) at a time, until blended; scrape down the bowl as needed.
5. Add vanilla extract and beat until blended.
6. Cover and refrigerate overnight to develop flavor.
7. In a small bowl, mix remaining ¼ cup (50 grams) granulated sugar and remaining ¾ teaspoon (1.5 grams) tea.
8. Cover and let stand overnight on the counter to develop the flavor.
9. Remove the dough from the refrigerator and let the dough stand at room temperature until soft enough to work with, about 30 minutes.
10. Using a scoop or rounded tablespoon, shape the dough into 1-inch (3-centimeter) balls and roll in the sugar mixture.
11. Arrange on prepared cookie sheets about 2 inches (6 centimeters) apart.
12. Bake each sheet until the cookies are lightly golden brown, 10–12 minutes.
13. Let cool on the pan for 5 minutes.
14. Move the cookies to a wire rack to let cool completely.

Make the glaze:

1. In a bowl, combine brewed tea, confectioners’ sugar, and vanilla extract.
2. Place the cooled cookies on a rack over a sheet pan.
3. Drizzle the cookies with the glaze and let stand until the glaze is set.

Variations:

Traditional Sugar Cookies
Follow recipe steps 1–2. In step 3, omit tea and zest. Omit step 4. In step 5, roll the balls in coarse sugar. Bake and let cool as directed. Omit step 8.

Cinnamon Sugar Cookies
Follow recipe steps 1–2. In step 3, omit tea and zest; add 1 teaspoon (2 grams) ground cinnamon with the flour. Omit step 4. In step 5, mix ¼ cup (50 grams) granulated sugar and 2 teaspoons (4 grams) ground cinnamon; roll the balls in the cinnamon mixture. Bake and let cool as directed. Omit step 8.

Pro Tips:
To prevent cookies from spreading too thin, chill the dough prior to baking.