Preheat oven to 350 degrees. Prepare 2 baking sheets by lining them with parchment paper and set aside.
In a mixing bowl, cream together the sugar, brown sugar, butter, shortening, and vanilla until light and fluffy.
Add eggs and mix until well combined.
Add flour, baking soda, cream of tartar, and salt. Mix just until all the dry ingredients are blended in.
For the cinnamon sugar mixture: In a small bowl, stir together the sugar and cinnamon.
Divide dough into 10 equal scoops. Roll into balls and toss in the cinnamon sugar mixture, making sure to coat the entire surface of each ball. Place on parchment paper lined baking sheets. I baked 6 cookies on one sheet, and four cookies on the next sheet. These bake best one sheet at a time.
Bake in a preheated 350 degree oven for around 18 to 20 minutes. All ovens are different, so baking time will vary. Keep close check on the browning, and try not to over bake. Allow to cool at least 5 minutes on baking sheet before transferring. Enjoy!! These are one of my childhood favorites!