Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper or a silicone baking mat.

1. In a large mixing bowl, beat together the softened butter and 1 ½ cups of granulated sugar until light and fluffy, about 2-3 minutes.
2. Add the eggs, one at a time, mixing well after each addition. Stir in the vanilla extract.
3. In a separate bowl, whisk together the all-purpose flour, cream of tartar, baking soda, and salt.
4. Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix.
5. Scoop about 1-2 tablespoons of dough and roll it into a ball. Place the dough balls onto the prepared baking sheet, spacing them about 2 inches apart.
6. In a small bowl, combine 2 tablespoons of granulated sugar and 2 teaspoons of ground cinnamon for the cinnamon-sugar coating. Roll each dough ball in the cinnamon-sugar mixture, coating it evenly on all sides.
7. Gently flatten each dough ball with the back of a spoon or your fingers to help the cookies bake evenly.
8. Bake for 10-12 minutes, or until the edges are golden but the centers are still soft. Be careful not to overbake them, as they should remain chewy.
9. Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.
10. Serve and enjoy your delicious Crumbl Snickerdoodle Cookies!