In a large mixing bowl cream at medium speed butter, sugar and eggs until light and fluffy. Scraping sides of bowl occasionally. In a separate bowl, combine flour, cream of tartar, baking soda and salt. Add to creamed mixture until well blended. Refrigerate dough 30 minutes.
Preheat oven to 375 degrees.
Combine the sugar and cinnamon. form dough into balls (walnut sized) and roll in sugar-cinnamon mixture. Place 2" apart on baking sheet. Bake about 10 to 12 minutes or until golden brown. Remove and cool on rack. Snickerdoodles will puff up at first and then flatten out during baking.
