Preheat the oven to 350°F with racks in the upper and lower thirds. Line 2 baking sheets with parchment, or lightly grease.

To prepare the tea: Cut open all the tea bags and empty them into a small bowl. If using tea with larger pieces, crush the tea leaves (in a mortar and pestle or using a plastic bag and a rolling pin) to achieve a finer consistency, with no large or woody pieces remaining. You should have 2 generous tablespoons of crushed tea leaves (about 14g). Set aside ½ teaspoon for the topping.

To make the dough: In the bowl of a stand mixer fitted with the flat beater attachment, combine the sugar, zest, and 2 tablespoons (about 12g) of the tea. Mix for 2 minutes on medium speed until the sugar is moist and fragrant.

Add the butter and beat on medium speed until the mixture is homogeneous, about 1 minute, scraping the bowl halfway through.

Add the egg and vanilla and beat on low speed until thoroughly combined, about 30 seconds.

In a medium bowl, whisk together the flour, baking powder, salt, and baking soda. Add the dry ingredients to the butter-sugar mixture in 2 additions, beating on low speed for about 20 seconds after each addition and scraping the bowl as needed, until the batter has only a couple streaks of dry flour remaining. Use a flexible spatula to scrape the bowl and incorporate the remaining dry flour.

To prepare the coating: In a small bowl or shallow pan, combine the sugar and the reserved ½ teaspoon tea leaves.

Using a tablespoon scoop or a generous tablespoon measure, scoop 3 or 4 pieces of dough and roll or toss them in the sugar mixture, coating evenly; for perfectly round cookies, roll the dough into neat balls before coating. Transfer to a prepared baking sheet, spacing evenly. Continue until you’ve filled the prepared baking sheets with 12 cookies each.

Bake the cookies for 10 to 12 minutes, rotating the baking sheets top to bottom and front to back halfway through, until the edges are set and just beginning to turn golden but the centers are still soft.

Allow the cookies to cool on the baking sheets for 5 minutes before transferring them to wire racks to cool completely.

Portion, coat, and bake the remaining cookie dough in the bottom third of the oven.

Serve the baked cookies at room temperature.

Storage information: Store Earl Grey cookies in an airtight container at room temperature for up to 4 days. The tea flavor will get stronger over time.