Remove the wrappers from the Kisses and set aside.
Add the flour, cocoa powder, and salt to a mixing bowl and whisk together. Set aside.
In a large bowl, beat together the butter, 1 ⅓ cups sugar, egg yolks, milk, and vanilla extract. Gradually add the cocoa mixture to the butter mixture, beating until well blended. Refrigerate the dough for 1 to 2 hours.
Use a 1 tablespoon cookie scoop to shape the dough into 48 balls. Roll each ball in sugar and place on a parchment lined baking sheet.
Bake at 350 degrees for 10-12 minutes. Remove from the oven and allow to cool for 1 minute. Press a peppermint Kiss into the center of each cookie.
Transfer the cookies to a wire rack to cool completely.