Preheat the oven to 350 degrees.  Line your baking sheet with parchment and set aside.

In the bowl of a stand mixer, cream together the butter, brown sugar and sugar.  

Add in the egg and vanilla and mix until smooth. 

Switch the mixer attachment to the paddle.  Add in the flour, corn starch, cream of tartar, baking soda, baking powder, cinnamon and salt. Mix until the dough pulls away from the side of the bowl and the mixture is crumbly but presses together. 

In a small bowl, combine the sugar and cinnamon for the coating.  Set aside. 

Divide the cookie dough into 9 equal size balls.  Round in the cinnamon and sugar mixture to coat. 

Place each cinnamon sugar coated cookie dough ball on your baking sheet.  Using the bottom of a drinking glass or similar flat-bottom object, flatten the dough until it is about ¾ of an inch thick.  Sprinkle with a little extra cinnamon and sugar mixture. 

Bake in the preheated oven for 10 minutes.  The cookies should be soft and chewy in the center so do not overbake. 

Allow to cool while making the frosting. 

In the bowl of a stand mixer, combine the softened cream cheese, butter, and vanilla.  

Add in the powdered sugar one cup at a time and mix until smooth.  

Transfer the frosting to a piping bag fitted with a large star tip - we used 2D.

Starting in the center of the cookie, pipe a continuous spiral of frosting on top of the cookie, stopping just inside the edge so the jagged rim of the cookie is still visible.  

Sprinkle with additional cinnamon to garnish.

Storage:  Cookies can be stored in an airtight container for 3 days in the fridge or frozen for 3 months.