Now:

In a medium bowl, combine the flour, cream of tartar, baking soda, and salt, and mix well. In a large bowl, combine the butter and sugar, beating with an electric mixer until smooth. Add the eggs, one at a time, mixing well after each. Add the vanilla and mix well. Add the flour mixture, one-third at a time, mixing well after each addition. Cover and refrigerate for 1 hour or up to 1 week.

Later:

Preheat the oven to 400°F. In a small bowl, combine the cinnamon and sugar, and set aside. Roll the dough into balls the size of small walnuts and then roll them in the cinnamon mixture. Place the coated balls on an ungreased baking sheet, about 2 inches apart. Bake for 8 to 10 minutes, until lightly browned. (The cookies will puff up and then flatten out with a crinkled top.)