Preheat the oven to 350 degrees Fahrenheit. Grease a half sheet pan (18 in. by 13 in.).

In the bowl of an electric mixer, cream together butter, granulated sugar, brown sugar, peppermint extract, eggs, and sour cream. Small lumps of butter will still remain.

In a separate bowl, whisk together flour, baking soda, cream of tartar, and salt. Add flour mixture to the wet mixture and mix just until combined, scraping down the sides as necessary. Just before it is finished mixing, add the 25 chopped candy cane kisses and quickly mix it in. Don't over mix after adding the flour mixture!

Press the dough evenly into the greased half sheet pan.

Bake for approximately 10-12 minutes. Don't overbake or they'll be dry! Set the timer for 9 minutes and check often.

Let them cool completely, then prepare the glaze. For the glaze, whisk together powdered sugar and milk until smooth and drizzling consistency. Drizzle evenly over the cooled bars. Immediately sprinkle with the additional 12 chopped Candy Cane Kisses. Slice into bars and serve.