Preheat oven to 375 degrees
Line two large cookie sheets with parchment paper or silicon baking mats
Make the topping by combining the sugar and cinnamon in a small, shallow bowl
Beat the sugar and butter together on high speed using a hand mixer or stand mixer with the paddle. After about two minutes, it should be smooth and creamy. Add the egg and vanilla extract, and beat on medium speed until combined. You will likely need to scrape the sides and bottom of the bowl to assure mixing.
In another bowl, sift together the remaining dry ingredients (I just use a whisk to combine them).
Return to the bowl with the sugar, butter, and egg mixture. With the mixer running at low speed, add the dry ingredients in thirds, mixing thoroughly between additions. The resulting dough will be thick.
Roll the dough into balls about 1.5 inches thick--about 1.5 TBSP of dough per ball. Roll each ball in the topping mixture and place about 2-3 inches apart on the cookie sheets.
Bake cookies for ten minutes. They will flatten some while baking, but still be puffy. Remove from the oven and use a fork to press down on each cookie to flatten slightly. Let cool on the baking sheet for at least ten minutes, then transfer to wire rack to finish cooling.
