Preheat oven to 375°F and line 3 baking sheets with parchment.
In a large bowl, whisk the flour, cream of tartar, baking soda, and salt together; set aside.
2¾ cups Bob's Red Mill Organic All-Purpose Flour, 2 teaspoons cream of tartar, 1 teaspoon Bob's Red Mill Baking Soda, ½ teaspoon kosher salt
In the bowl of a stand mixer fitted with the paddle attachment, cream the shortening and butter together for 30 seconds. Add 1½ cups sugar and beat until lighter in color and fluffy, about 3 minutes.
½ cup vegetable shortening, ½ cup unsalted butter, 2½ cups granulated sugar
Beat in eggs, one at a time, just until incorporated.
2 large eggs
Add the flour mixture (all at once) to the creamed butter mixture and mix on low just until no flour is visible. Do not over work the dough or the cookies will be tough.
Set up a “work station” near the baking sheets with a bowl of cinnamon and the remaining 1 cup sugar and a bowl of iced water. Set a folded paper towel next to the water bowl.
¼ cup ground cinnamon, 2 cups iced water
Gently roll 2 tablespoons dough into a ball, dip the dough into the iced water and briefly place it on the paper towel (to absorb excess water). Roll the cookie dough ball in the cinnamon/sugar and set it on a baking sheet. Repeat with all the dough, spacing the balls 2-inches apart. There should be 8 cookies per sheet.
Bake the cookies, on the middle rack at 375°F for 10-12 minutes (rotating after 6 minutes). The cookies are done when the edges are just set and barely browning, and the centers are soft, cracked, and will look slightly undercooked.
Cool the cookies 5-8 minutes on the baking sheet then transfer to a cooling rack.