- 1 cup unsalted butter, slightly softened, plus 4 tablespoons
- ¾ cup granulated sugar
- ¼ teaspoon fine salt
- 1½ teaspoons peppermint extract or flavor, plus a drop for sanding sugar
- 1 large egg
- 2½ cups all-purpose flour
- 1 cup semi-sweet chocolate chips
- Green sanding sugar
In bowl of an electric mixer fitted with paddle attachment, combine butter, sugar, salt, peppermint extract, and egg. Beat on medium-high speed until light and fluffy, scraping bowl as necessary. Reduce speed to low and gradually add flour, scraping bowl as necessary, until a soft dough forms. Divide dough into two portions, form into 1-inch-thick disks, and wrap in plastic wrap. Refrigerate for at least 15 minutes or until ready to use.
Heat oven to 350°. Working with one dough at a time, roll dough out on a lightly floured work surface until ¼-inch-thick. Use a 1.-inch round cutter to stamp out cookies. Place on parchment-lined baking sheet and bake until set, about 8 minutes, rotating halfway through baking time. Cool on a wire rack.
Combine chocolate and 4 tablespoons butter in medium bowl set over a pot of simmering water. Stir until melted and smooth. Sandwich a dab of chocolate between each cookie. Drizzle with remaining chocolate, moving rapidly from left to right. Combine a drop of peppermint extract with ¼ cup of sanding sugar and sprinkle over cookies.