Makes 4 dozen For the cookies: ½ pound (2 sticks) unsalted butter, at room temperature 1 ½ cups sugar 2 large eggs, at room temperature 2 ¾ cups all-purpose flour 2 teaspoons cream of tartar 1 teaspoon baking soda ½ teaspoon kosher salt Cinnamon sugar for rolling: 2 tablespoons sugar 1 tablespoon ground cinnamon To make the cookies: Put the butter and 1 ½ cups sugar in a large mixing bowl and using a spoon or rubber spatula, mix until smooth. Add the eggs and mix again. Add the flour and then sprinkle in the cream of tartar, soda and salt. Mix until everything is well incorporated. Scrape down the sides of the bowl and mix again. To make the cinnamon sugar: Put the 2 tablespoons sugar and cinnamon on a plate and mix until well combined. To form the cookies: break off tablespoon size pieces of dough and roll into 1 inch balls. Roll the balls in the cinnamon sugar and place 2 inches apart on the prepared cookie sheet. Cover and refrigerate at least 2 hours and up to overnight. Preheat the oven to 375 degrees. Line a cookie sheet with parchment or wax paper.
Put the dough on the prepared sheet and, using your hand or the bottom of a water glass, press down until flattened. Put the cookie sheet in the oven and bake until the cookies begin to brown at the edges, about 8- 10 minutes. Cool on the cookie sheet and then transfer to a plate. Repeat with the remaining dough