In a separate large bowl, whisk together the 3 cups all-purpose flour, 2 tablespoons powdered milk, 2 teaspoons cream of tartar, and 1 teaspoon baking soda.
In a stand mixer fitted with a paddle attachment, cream together 1 cup salted butter, 1 cup granulated sugar, ⅓ cup light brown sugar, and ½ teaspoon kosher salt on high for 2 minutes until the mixture is pale and fluffy.
Scrape down the sides and add in the 1 large egg, 1 additional large egg yolk, and 1 tablespoon vanilla extract and mix just until combined.
Add the dry ingredients to the wet ingredients in three different parts, mixing between each addition. Scrape down the sides as needed and mix until fully incorporated.
Chill the dough for 30 minutes before shaping. Meanwhile, mix together ¼ cup granulated sugar and 1½ teaspoons ground cinnamon for the first coating and set aside.
Preheat the oven to 375 degrees F and line a large baking sheet with parchment paper and set aside.
Use a #20-sized cookie scoop to measure the dough, roll it into balls, and then roll each ball in the cinnamon sugar mixture before placing it on the cookie sheet.
Ensure cookies are 4 inches apart and bake for 9 to 11 minutes.
Discard the old cinnamon sugar coating and make a fresh batch with ¼ cup granulated sugar and 1½ teaspoons ground cinnamon for the second coating.
Let the cookies cool on the baking sheet for a few minutes to firm up a bit before dipping the tops of the cookies in the second batch of cinnamon sugar and transferring them to a cooling rack.