In a medium bowl, whisk together flour, salt and baking soda. In a large bowl using either a hand or stand mixer, beat softened butter with granulated sugar until fluffy.
Add in egg and peppermint extract, beating until smooth. Add in flour mixture in three separate additions, beating after each addition until all of the flour mixture is incorporated. Cover and refrigerate cookie dough for at least one hour.
Preheat oven to 350 F. Roll cookie dough into balls and place onto ungreased baking sheets 2-inches apart. Bake for 10-12 minutes. Remove from oven and place one chocolate kiss on each cookie.
