How to Make It
Preheat the oven to 375º. In a large mixing bowl or stand mixer, beat 1 1/2 cups of the sugar with the butter and shortening until smooth. Beat in the eggs. Stir in the flour, cream of tartar, baking soda and salt.
Shape the dough into 1-inch balls. Mix 1/4 cup of the sugar and the cinnamon. Roll balls in the cinnamon-sugar mixture and place on greased cookie sheets, equally spaced apart. Bake for 10 minutes. Remove from oven and let cool for 2 minutes before moving to wire rack to cool completely.