Mocha-Peppermint Mosaic Slice-and-Bake Butter Cookies

Steps

1. 1

   Whisk the all-purpose flour, table salt, and baking powder together in a medium bowl.

2. 2

   In a second bowl, whisk the melted and cooled butter, granulated sugar, egg yolk, and peppermint extract until the mixture is very smooth.

3. 3

   Add the flour mixture to the butter mixture and stir with a rubber spatula or wooden spoon until well combined. Note that the dough will be loose.

4. 4

   Let the dough rest until firm, about 5 minutes.

   Start 5-minute timer
5. 5

   Shape the dough into a rough 8 by 5-inch rectangle. Wrap it tightly in plastic wrap and refrigerate until firm, at least 1 hour or up to 3 days.

   Start 1-hour timer
6. 6

   Sift the instant espresso powder, cocoa powder, confectioners' sugar, and dry milk powder through a fine-mesh strainer into a medium bowl.

7. 7

   Cut the chilled dough into rough 3/4-inch pieces.

8. 8

   Add the dough pieces to the espresso-cocoa mixture and toss until the pieces are evenly coated.

9. 9

   Transfer the pieces to a counter, shaking the excess espresso-cocoa mixture back into the bowl; do not discard this mixture. Divide the dough pieces into 2 equal piles.

10. 10

    Working with one pile, firmly squeeze one-quarter of the pieces together to form a dough ball with streaks of the espresso mixture throughout. Do not knead the dough.

11. 11

    Repeat with the remaining three-quarters of that dough pile to form 3 more balls. Squeeze and press the 4 dough balls together to form a rough 8-inch log.

12. 12

    Continue to shape and roll the log until it is 1 1/2 inches in diameter and about 9 inches long. Flatten the log slightly on two sides until it is 1 inch tall and has an oval shape. Repeat the entire process with the second dough pile to form a second log.

13. 13

    Transfer the reserved espresso-cocoa mixture to the counter and roll both logs in the mixture to coat them evenly.

14. 14

    Wrap the logs tightly in plastic and refrigerate until firm, about 30 minutes.

    Start 30-minute timer
15. 15

    Adjust an oven rack to the middle position and preheat the oven to 350°F (180 °C) (175°C (350 °F)). Line 2 rimmed baking sheets with parchment paper.

16. 16

    Slice the logs into 1/4-inch-thick ovals and space them 1 inch apart on the prepared baking sheets.

17. 17

    Let the sliced dough rest at room temperature for 10 minutes before baking to help them expand evenly.

    Start 10-minute timer
18. 18

    Bake the cookies, one sheet at a time, until puffed and the tops look dry but the centers are still very soft, 10 to 12 minutes, rotating the sheet halfway through baking.

    Start 12-minute timer
19. 19

    Let the cookies cool on the sheet for 10 minutes, then transfer them to a wire rack to cool completely, about 30 minutes.

    Start 10-minute timer