Preheat the Oven:
Preheat your oven to 375°F (190°C). Line baking sheets with parchment paper or silicone baking mats.
Cream the Butter and Sugar:
In a large mixing bowl, beat the softened butter and 1 1/2 cups of granulated sugar together until light and fluffy. This should take about 2-3 minutes.
Add Eggs:
Add the eggs one at a time, beating well after each addition.
Mix Dry Ingredients:
In a separate bowl, whisk together the flour, cream of tartar, baking soda, and salt.
Combine Wet and Dry Ingredients:
Gradually add the dry ingredients to the butter mixture, mixing until just combined.
Prepare Cinnamon-Sugar Coating:
In a small bowl, mix the 3 tablespoons of granulated sugar with the ground cinnamon.
Form the Cookies:
Using a small cookie scoop or spoon, form the dough into 1-inch balls. Roll each ball in the cinnamon-sugar mixture to coat.
Bake:
Place the coated dough balls on the prepared baking sheets, spacing them about 2 inches apart. Bake for 8-10 minutes, or until the edges are set but the centers are still soft.
Cool:
Allow the cookies to cool on the baking sheets for a few minutes before transferring them to a cooling rack to cool completely.