With an electric mixer, combine the butter and sugars for 3 minutes until light and fluffy.
Add the egg and vanilla, and beat on medium-high speed about 3 minutes.
Add the flour, baking soda, cream of tartar, optional salt, and beat on low speed until just combined, about 1 minute.
Roll out 1 tablespoon-sized balls of dough (approximately 25 cookies) and refrigerate for at least 1 hour.
Preheat oven to 350F, line a baking sheet.
Roll the cookie dough balls in the cinnamon sugar mixture and set out 2″ apart on the baking sheet.
Bake 8-10 minutes until edges are browned and crisp, but center is still pale and puffy. They will wrinkle as they cool.