In a medium-size bowl, using an electric mixer, beat together butter and shortening for 30 seconds
Add 1 ¾ cup sugar and vanilla. Beat on medium-high until fully combined.
Add eggs one at a time beating well after each addition. Scrape the sides of the bowl periodically.
In a separate bowl, sift together flour, baking soda, cream of tartar, salt and ½ tsp cinnamon. (A whisk works perfectly)
Lower the speed of the mixer and gradually add dry ingredients beating until fully combined.
Chill dough for at least 2 hours or overnight.
To prepare: Preheat oven to 375°F. Line 2 baking sheets with parchment paper. Set aside
Mix together ¼ cup sugar and 2 tsp cinnamon in a shallow bowl. Form dough into small balls and roll in mixture.
Arrange dough balls on cookie sheet at least 2 inches apart. Bake for 8-10 minutes.
Carefully remove to cooling rack to cool completely. Store at room temperature in an airtight container.