In a large mixing bowl, sift together the all-purpose flour, cream of tartar, baking soda, and salt. Set aside.

In the bowl of a stand mixer fitted with the paddle attachment, combine the unsalted butter and 1½ cups of sugar. Cream on medium speed for approximately 2 minutes, or until the mixture is light and fluffy. Scrape down the sides of the bowl with a rubber spatula as necessary to ensure even mixing.

Add the eggs, one at a time, mixing on medium speed until fully combined—about 30 seconds. Scrape down the sides of the bowl again, if needed.

Add the dry flour mixture to the butter mixture. Mix on low speed just until the dough forms and ingredients are fully incorporated, approximately 30 seconds. Avoid overmixing.

Shape the dough into a disk, wrap tightly in plastic wrap, and refrigerate for at least 1 hour or preferably overnight to allow the dough to firm and the flavors to meld.

Adjust oven racks to the upper- and lower-middle positions. Preheat oven to 400°F (200°C). Line two baking sheets with parchment paper and set aside.

If the dough was refrigerated overnight, allow it to rest at room temperature for 10 minutes before shaping. In a shallow bowl, mix the remaining ¼ cup sugar and 2 tablespoons ground cinnamon. Scoop a heaping tablespoon of dough and roll it between moistened palms to form a ball approximately 1½ inches in diameter. Roll each dough ball in the cinnamon-sugar mixture, then place on the prepared baking sheets, spacing them about 2 inches apart.

Bake for 10 minutes, rotating the baking sheets halfway through the baking time to ensure even browning. The cookies should be set in the center and display slight cracking on top.

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