In a large mixing bowl, cream together softened butter and granulated sugar for about 3-4 minutes until light and fluffy. Add eggs one by one, mixing thoroughly after each.

In a separate bowl, whisk together flour, cream of tartar, baking soda, and salt. Gradually fold dry ingredients into the wet mixture until just combined.

Cover the bowl with plastic wrap and refrigerate the dough for at least 1 hour or up to overnight.

Preheat your oven to 350°F. In a small bowl, mix together granulated sugar and ground cinnamon for the coating.

Remove the chilled dough and roll into 1-inch balls. Roll each ball in the cinnamon-sugar mixture and place on baking sheets.

Bake in the preheated oven for 9-11 minutes until edges are golden and centers slightly underdone. Allow cookies to cool on the sheet for 2-3 minutes.