Preheat your oven to 375°F (190°C).
In a mixing bowl, cream together the butter and 1.5 cups of sugar until light and fluffy.
Add the eggs one at a time, beating well after each addition.
In another bowl, whisk together the flour, cream of tartar, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
In a small bowl, mix together the 2 tablespoons of cinnamon and 0.25 cup of sugar.
Roll the dough into 1.5-inch balls and coat each ball in the cinnamon-sugar mixture.
Place the coated dough balls onto a baking sheet, spacing them about 2 inches apart.
Bake for 8-10 minutes, until the edges are set but the centers are still soft.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.