Step 1
Preheat oven to 375°F. Line 2 baking sheets with parchment paper. Set aside.
Step 2
In a medium bowl, with an electric mixer, cream butter, shortening, and 1 ½ cups of sugar until light and fluffy. About 2 minutes. Add eggs, one at a time, and vanilla. Beat until well incorporated. Scrape the sides of the bowl as needed.
Step 3
Add cream of tartar, baking soda, salt, and flour. Mix until all ingredients are well combined.
Step 4
In a medium bowl, mix remaining 1 cup of sugar with cinnamon. Using a small ice cream scooper, scoop balls of dough into the cinnamon-sugar mixture. Coat the balls completely.
Step 5
Transfer the balls of dough onto the prepared pans. Flatten the dough gently with your hand.
Step 6
Bake for 8-10 minutes or until golden brown. Remove the cookies from the oven and transfer to a cooling rack.
