Preheat oven to 400°F
In a large bowl, thoroughly mix flour, salt, and sugars together.
In another bowl, mix together baking soda and cream of tartar. Then, add this to the bowl of dry ingredients. Incorporate into the dry ingredients.
Add slightly softened butter and shortening to dry ingredients.
In another bowl, lightly whisk eggs and vanilla extract together, and then add to dry ingredients.
In a shallow bowl, add ¼ cup sugar and 2 tbsp. Cinnamon. Mix thoroughly.
Form a small ball of dough in your hands, and roll the dough-ball in the cinnamon/sugar mixture. Place rolled dough onto baking sheets.
Bake at 400°F for 10-12 minutes. Makes approx. 36 cookies.