1. Preheat oven to 400 degrees F.
2. Cream together butter, shortening. Add the sugar and mix well. Blend in the eggs and the vanilla until light and fluffy. Hand stir in the flour, cream of tartar, soda and salt. Shape dough by rounded spoonfuls into balls.
3. Mix some cinnamon and sugar on a plate (I like to make sure they are good and covered so I use lots of sugar and cinnamon, just do the amounts that feel right). Roll balls of dough in mixture. Place 2 inches apart on ungreased baking sheets.
4. Bake 5 to 7 minutes. Remove immediately from baking sheets and place on cooling racks, wax paper, paper towels… pretty much whatever you have to work with.