Preheat the oven to 350°. Line 2 large baking sheets with parchment paper. In a medium bowl, whisk together flour, cream of tartar, baking soda, and salt.

In a separate bowl using a hand mixer, beat butter with 1 cup granulated sugar and the brown sugar until light and fluffy, about 2 minutes.

Add the eggs, one at a time and beat to combine. Fold dry ingredients in until combined.

In a shallow bowl, combine remaining ¼ cup of sugar with cinnamon.

Using a medium cookie scoop, scoop and roll the dough into 1 1/2"-inch balls, then roll balls in cinnamon sugar. Arrange about 2" apart on prepared baking sheets.

Bake until the cookies begin to crack, about 12 minutes. Let cool on the trays 5 minutes, then use a thin metal spatula to transfer cookies to a wire rack to cool completely.