Move oven racks to the middle position, and preheat oven to 375 degrees F. Line 2 cookie sheets with parchment paper or silicone baking mats, and set aside.

In a medium bowl whisk together the flour, cream of tartar, baking soda, and salt. Set aside. In a large bowl add the butter and 1 1/2 cups of sugar.

Beat with a hand mixer on medium speed until fluffy and pale yellow in color, about 3 minutes. Add the eggs and beat until combined.

Slowly beat in the flour mixture in 3 additions until a cohesive dough forms.

In a small bowl combine the remaining 1/4 cup granulated sugar and cinnamon.

Using a 2-tablespoon scoop, scoop the dough and roll into balls. Then, roll the balls into the cinnamon sugar.

Place the dough 3 inches apart on the prepared baking sheets. Bake, 1 sheet at a time, until the edges are just set and beginning to turn light brown, about 10-12 minutes. The cookies will be soft in the center and still puffy. Cool the cookies on the cookie sheets for 15 minutes, and then transfer the cookies to a wire rack and cool completely.

Repeat with the remaining dough and cinnamon sugar, and serve once the cookies are cooled.