Adapted from Allrecipes
~from Savoring Time in the Kitchen
Makes about 48 cookies
1/2 cup butter, softened
1/2 cup shortening
1-1/2 cups white sugar (I only used 1 cup)
2 eggs - room temperature
2 teaspoons vanilla extract (optional)
2-3/4 cups all-purpose flour
2 teaspoons cream of tartar
1 teaspoon baking soda (baking soda should be less than 30 days old)
1/4 teaspoon salt
3 tablespoons white sugar
3 teaspoons ground cinnamon
Measure the flour, cream of tartar, baking soda and salt into a medium bowl and mix gently whisk with a fork. Set aside.
Mix the 2 T sugar and cinnamon together and place in a shallow bowl or into a plastic zip bag.
In a large bowl, mix together the softened butter, shortening and 1 1/2 cups sugar and mix with a wooden spoon until well combined but don't overwork the dough. Mix in the room-temperature eggs one-at-a-time until well combined. Stir in the vanilla if using. Add the flour mixture a little at a time until completed incorporated. Shape dough by rounded spoonfuls into balls about 1 inch or so in diameter. Roll the balls of dough in the cinnamon sugar or place them in the zipper bag and shake gently until thoroughly coated with the cinnamon mixture. Place 2 inches apart on a silicone mat/parchment paper-lined baking sheet and chill for 15 minutes.
While the dough is chilling, preheat the oven to 400 degrees (200 celcius).
Bake 8-10 minutes, or until set but not too hard. Remove immediately from baking sheet.