1. Prepare the Crust:

1. Preheat oven to 350°F (175°C) and line baking sheets with parchment paper.
2. In a large bowl, cream together the softened butter and 1 1/2 cups sugar until light and fluffy. Beat in the eggs one at a time.
3. In a separate bowl, whisk together the flour, cream of tartar, baking soda, and salt. Gradually mix into the butter mixture until just combined.
4. In a small bowl, mix the 2 tablespoons sugar and cinnamon. Roll dough into 1-inch balls, then coat each in the cinnamon-sugar mixture.
5. Place dough balls 2 inches apart on prepared baking sheets. Bake for 10-12 minutes, until edges are lightly golden. Cool on baking sheet for 5 minutes before transferring to a wire rack.