2 sticks (8 ounces) unsalted butter at room temperature
¾ cup granulated sugar, plus extra for rolling
2¼ cups all-purpose flour
1 tablespoon plus 1 teaspoon finely chopped loose-leaf rooibos tea
¾ teaspoon kosher salt
3 tablespoons heavy cream
2 large egg yolks
1 teaspoon vanilla extract
1½ tablespoons turbinado sugar
1 teaspoon finely chopped loose-leaf rooibos tea
1. Make the tea cookies: In a standing mixer with the paddle attachment, mix the butter and granulated sugar together on medium speed until light and airy, about 2 minutes.
2. In a medium bowl, whisk together the flour, tea leaves and salt. In another small bowl, whisk together the heavy cream, egg yolks and vanilla.
3. With the mixer on medium-low speed, alternate adding the flour mixture with the cream mixture in three additions, starting and ending with the flour mixture.
4. Turn half of the dough out onto a large sheet of plastic wrap and roll into a 6-inch-long by 3-inch-wide log. Wrap tightly and repeat with the remaining dough. Refrigerate until the dough is firm, at least 2 hours or up to three days (the cookie log can also be frozen for up to three months; defrost overnight before slicing).
5. Make the rooibos sugar: In a small bowl, stir together the turbinado sugar and tea leaves. Set aside.
6. Adjust one oven rack to the upper-middle position and another oven rack to the lower-middle position. Preheat the oven to 375°. Unwrap one chilled dough log and place it on a clean work surface. Let the dough warm up for 5 to 10 minutes. Sprinkle the rooibos sugar on the work surface and roll the cookie log in the sugar until completely coated on all sides. Slice the log into twelve ¼-inch-thick rounds.
7. Line two baking sheets with parchment paper and place the cookies 1-inch apart on the prepared sheets. Set one baking sheet on the upper oven rack and the other on the lower one. Bake for 7 minutes, then rotate the pans, moving the pan from the lower rack to the upper one, and the one from the upper rack to the lower one. Bake until golden brown around the edges, another 6 to 7 minutes. Remove the baking sheets from the oven and cool 5 minutes before using a spatula to transfer the cookies to a wire rack to cool completely. Serve the cookies warm or at room temperature.