In a small bowl, combine the baking soda and vinegar. Stir until baking soda is dissolved.
½ teaspoon baking soda, 1½ teaspoon white distilled vinegar
Cream the butter and sugar in the bowl of a stand mixer fitted with the paddle attachment. Mix on HIGH until the mixture is fluffy and creamy, about 3 minutes.
½ cup unsalted butter, ¾ cup granulated sugar
Add the egg and mix 1 minute.
1 large egg
Add the baking soda/vinegar and mix well.
In a medium bowl, whisk the flour and salt together and add to the creamed butter mixture. Mix on low just until the flour is incorporated.
2⅓ cups all-purpose flour, 1 teaspoon kosher salt
Transfer the dough to plastic wrap and shape into a disk; chill for 30 minutes.
Heat the oven to 350°F and adjust the oven rack to the middle position. Line 3 large baking sheets with parchment.
After the dough has chilled, place it on a lightly floured work surface and roll to ⅙-inch thickness.
Cut into rounds (I used 1¾-inch fluted rounds), and transfer the cut dough to the prepared baking sheets. The dough spreads very slightly, so leave about 1-inch between rounds.
Bake cookies at 350°F for 11-14 minutes, or until golden brown and crisp. (I prefer these cookies extra crispy.)
Transfer cookies to a cooling rack and completely cool before icing.
Melt the chocolate in the microwave on HIGH until melted and creamy. Stir every 15 seconds with a dry, clean rubber spatula.
6 ounces semisweet chocolate
Place the peppermint candies in a zipper-style plastic bag and crush with a rolling pin.
8 peppermint candies
When the cookies have cooled, spread with melted chocolate and sprinkle with crushed peppermints.
Let the chocolate set before serving and before storing.