-
1
Preheat oven to 325 degrees.
-
2
Sift flour, cocoa powder, baking soda, baking powder, and salt into a bowl.
-
3
Beat butter and sugar with a mixer on medium-high speed for 1 minute.
-
4
Reduce speed to medium-low, and add egg, then yolk, beating well after each addition.
-
5
Beat in peppermint extract.
-
6
Slowly add flour mixture, and beat until just incorporated.
-
7
Shape dough into 2 disks, wrap each in plastic, and refrigerate until firm, at least 1 hour (or up to 2 days).
-
8
Roll out 1 disk of dough on a lightly floured surface to 1/8-inch thickness.
-
9
Freeze until firm, about 15 minutes.
-
10
Using a 2-inch round cutter, cut out circles, and place 1 inch apart on parchment-lined baking sheets.
-
11
Roll and cut scraps once.
-
12
Freeze cookies until firm, about 15 minutes.
-
13
Repeat with remaining disk.
-
14
Bake until cookies are dry to the touch, about 12 minutes.
-
15
Transfer parchment, with cookies, to wire racks, and let cool.
-
16
(Undecorated cookies will keep, covered, for up to 3 days.)
-
17
Sift crushed candy, and separate larger pieces from dust, reserving both.
-
18
Melt chocolate in a heatproof bowl set over a pot of gently simmering water.
-
19
Remove from heat.
-
20
Dunk cookies into melted chocolate.
-
21
Using a fork, turn to coat, let excess drip off, and gently scrape bottom against edge of bowl.
-
22
Place on parchment-lined baking sheets, and sprinkle 1/4 teaspoon of either candy pieces or dust on top.
-
23
Repeat, sprinkling half the cookies with pieces and the rest with dust.
-
24
Refrigerate until set, up to 3 hours.
-
25
Decorated cookies are best served the same day.
