In a medium-size bowl, using an electric mixer, beat together butter and shortening for 30 seconds or so (until they are combined).
Add 1-¾ cup sugar and the vanilla. Beat on medium-high until combined.
Add the eggs, one at a time, beating well after each. Scrape the sides of the bowl periodically to ensure good mixing.
Ina separate bowl, sift together flour, baking soda, cream of tartar, salt and ½tsp cinnamon (A whisk works perfectly for this if you do not have a sifter).
Lower the speed of the mixer and slowly add dry ingredients, beating until fully combined.
Chill the dough for at least 2 hours. Best if you can do it overnight.
Once the dough is chilled, preheat your oven to375°F. Line your baking sheets with parchment paper or non-stick cooking spray. Set them aside.
In a small bowl, mix together ¼ cup sugar and 2 tsp cinnamon. Form the cookie dough into small balls and roll them in the mixture.
Arrange the dough balls on a cookie sheet (give them about 2 inches of space from one another). Bake for 8-10 minutes.
Carefully remove to cooling rack to cool completely. Store at room temperature in an airtight container.