Preheat your oven to 350°F (175°C). Line baking sheets with parchment paper or silicone baking mats.

In a large bowl, beat the softened butter and 1½ cups sugar together until light and fluffy using an electric mixer.

Add the eggs one at a time, mixing well after each addition, then stir in the vanilla extract.

In a separate bowl, whisk together the flour, cream of tartar, baking soda, and salt.

Gradually add the dry mixture to the wet ingredients, mixing until just combined into a soft cookie dough.

In a small bowl, mix together the ⅓ cup sugar and 2 tablespoons cinnamon for the coating.

Scoop dough by rounded tablespoons and roll each portion into a ball. Roll the balls in the cinnamon-sugar coating until fully covered.

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 and the tops have begun to crackle.

Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.