Preheat oven to 375. Line a 9x13 inch baking pan with foil and lightly grease the foil.
In a medium bowl whisk together flour, baking powder, and salt. Set aside.
In a large bowl, cream the butter until light and fluffy (about 1 minute). Add sugars and mix until combined. Add egg, sour cream, and vanilla and mix well. Gradually mix flour mixture into wet ingredients and continue to mix until the dough comes together and is not crumbly. Gently fold in the chopped Hershey Kisses Candies.
Gently press the dough into bottom of prepared baking dish. Bake 18-22 minutes until golden. Allow to cool completely.
Once the bars have cooled, prepare the frosting. In a large bowl, beat the softened cream cheese and butter until fluffy. Add the powdered sugar and peppermint extract and beat until creamy. Add a tablespoon of milk at a time until the frosting reaches the consistency you desire. Frost the cooled bars. Sprinkle with additional chopped Hershey's Kisses Candy Cane Mint candies. Cut into bars and enjoy.
Recipe by About A Mom at https://www.aboutamom.com/peppermint-sugar-cookie-bars/