2 3/4 cups flour
2 teaspoons cream of tartar
1 teaspoon baking soda
1/4 teaspoon salt
2 stick or 8 ounces unsalted butter, at room temperature
1 3/4 cups sugar, plus more if needed
2 tablespoons ground cinnamon, plus more if needed
Preheat the oven to 400°.
Sift together flour, cream of tartar, baking soda, and salt; set aside. In the bowl of an electric mixer fitted with a paddle attachment, combine butter and 1 1/2 cups sugar. Beat on medium speed until light and fluffy, about 2 minutes. Scrape down sides of bowl. Add eggs, and beat to combine. Add dry ingredients, and beat to combine. At this point, I chilled the dough for at least an hour before scooping it.
Once dough has chilled, in a small bowl, combine remaining 1/4 cup sugar and the ground cinnamon. Use a small ice-cream scoop to form balls of the dough, and roll in cinnamon sugar. Place about two inches apart on the prepared baking sheets. Bake until the cookies are set in center and begin to crack (they will not brown), about 10 minutes, rotating the baking sheets after five minutes.
Thanks Smitten Kitchen.