Iced Peppermint Cookies

In a large bowl, sift together flour, salt and baking powder.

In an electric mixer fitted with the paddle attachment, beat together butter and granulated sugar on medium speed until fluffy and lightened in color, 2 to 4 minutes. Beat in egg yolk and peppermint extract. With mixer set on low, gradually add flour mixture, beating until just incorporated, scraping down the bowl as needed.

Gather dough into a ball and press it into a 1-inch-thick disk. Wrap in plastic wrap, and refrigerate for at least 1 hour. (The dough can be made up to 5 days ahead and stored in the refrigerator, or frozen for up to 2 months. Thaw it overnight in the fridge.)

When ready to bake, heat the oven to 350 degrees. Line 2 sheet pans with parchment paper.

Unwrap the disk of dough out onto a sheet of parchment paper and place another parchment sheet over the top. Roll the dough until it’s ¼-inch thick then remove the top parchment. Use a floured 2-inch-round cookie cutter to stamp out the cookies, and transfer them to the prepared baking sheets, spacing at least ½ inch apart. Reroll the scraps as needed, creating more cookies.

Bake until the cookie edges and bottoms are brown, rotating the pan once halfway through baking, 13 to 17 minutes. Transfer the cookies to wire racks and cool completely.

Make the royal icing: In the bowl of an electric mixer fitted with the whisk attachment, combine the powdered sugar, egg whites, cream of tartar, salt and peppermint extract. Whisk on high until stiff and glossy, adding water if needed so that the icing runs off a spoon. Taste and add a little more peppermint if needed. It should be deeply flavored. (The peppermint flavor of these cookies fades over a few days. So if you plan on keeping them for more than a day or two, use a greater amount of peppermint extract.)

To tint, divide the icing into two small bowls. Cover the contents of one bowl — you’ll leave it white — with plastic wrap, as it’ll dry out very quickly. Use a rubber spatula to stir in red coloring into the other until it’s vibrant. Tap the bottoms of the bowls to remove any air bubbles.

Working one at a time, spoon the red icing on one half of the cookie, aiming for a straight line through the center of the circle. Once the icing is dry, spoon the white icing on the blank side of the cookie and let sit to set.