Preheat the oven to 350°F. Grease or line 2 baking sheets or cookie sheets with parchment paper.
Whisk together in a medium bowl until well blended:
Beat in a large bowl until light and fluffy:
Add one at a time and beat until well incorporated:
Stir in the flour mixture until just combined. Combine in a small bowl:
Shape the dough into 1 ¼-inch balls, roll in the cinnamon sugar, and arrange about 2 ¾ inches apart on the prepared baking sheets. Bake until the cookies are light golden brown at the edges, 12 to 14 minutes, switching oven racks and rotating the sheets halfway through. Let cool on the sheet for 2 or 3 minutes, then transfer to a wire rack to cool completely.