Homemade Thin Mints

Found online at this website - first year made 2019 by Dom

Ingredients

For the cookie

• 2 cups (260 g) all-purpose flour
• ½ cup (42 g) dark cocoa powder
• ½ teaspoon salt
• 1 cup (226 g) unsalted butter, softened
• ⅔ cup (133 g) granulated sugar
• 1 large egg white
• 1 teaspoon vanilla extract
• ½ teaspoon peppermint extract

For the coating

• 12 ounces (339 g) dark or semisweet chocolate, coarsely chopped
• ½ teaspoon vegetable oil
• ¼ teaspoon peppermint extract

Instructions

Make the cookies

1. In a medium bowl, combine the flour, cocoa powder, and salt. Stir with a whisk; set aside.
2. Using a stand mixer fitted with the paddle attachment or with a hand-held mixer, beat the butter and sugar together on medium speed until smooth and creamy, about 3 minutes. Beat in the egg white followed by the vanilla and peppermint extract. The dough may appear curdled, this is normal. Gradually add the flour in 3 additions, beating just until incorporated after each one. Scrape down the sides of the bowl as needed. 
3. Divide the dough in half. Working with one half at a time. Place the dough between two pieces of parchment paper and roll it to a ¼ inch thickness. Leaving the dough in between the parchment paper, transfer it to a baking sheet. It's okay to stack the slabs of rolled dough. Refrigerate for at least 3 hours or freeze it for 1 hour.
4. Preheat the oven to 350°F. Line 2 baking sheets with parchment paper. 
5. Working with one disk at a time. Remove the top layer of parchment paper and cut circles with a 2-inch cookie cutter. Place the cookies on the prepared baking sheets about 1 and ½ inches apart. Gather the scraps of dough, reroll and chill to continue cutting and baking.
6. Bake for 15 to 18 minutes, until the cookies feel firm to the touch. Cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.

Make the coating

1. Combine the chocolate, oil, and extract in a medium heatproof bowl set over a pot of barely simmering water. Stir continuously until melted and smooth.
2. Using a fork, dip each cookie into the melted chocolate, turning to coat and tapping off any excess. Place cookies onto a parchment-lined baking sheet. Refrigerate the cookies until set, about 10 minutes. Cookies are best when served cold.

Notes

Adapted from Dorie's Cookies

Make ahead tip

1. The dough can be rolled out and kept in the refrigerator for up to 3 days or frozen for up to 2 months. Cut and bake as directed, even straight from the freezer.
2. Baked (uncoated or coated) cookies will keep for up to 7 days in an airtight container stored in the refrigerator or up to 2 months in the freezer.