In a medium bowl, stir together the all-purpose flour, cornstarch, baking soda, and salt. Set aside.
In a small bowl, add ¼ cup granulated sugar. Set aside.
In a large mixing bowl, beat together, on medium-low speed, the unsalted butter, and the remaining 1½ cups of granulated sugar for 1 minute. Add the large egg and vanilla extract and continue to beat for an additional 1 minute or until light and fluffy.
Slowly add the flour mixture to the butter mixture, on low speed, just until all the flour has been incorporated. Make sure to scrape down the sides of your bowl as needed.
Scoop out the chewy sugar cookie dough using a 1 ½ tablespoon (1 ½ inch) cookie scoop and roll each dough ball into the reserved bowl of granulated sugar. Place the sugar-coated dough balls onto a tray. Repeat until all the cookies are scooped and coated in granulated sugar.
Cover the tray of chewy sugar cookie dough balls with a piece of plastic wrap and refrigerate your dough for 1 hour. This allows the butter to firm up, so your cookies do not spread too much. You can skip the chilling step, but your cookies will be a bit flatter when baked.
Preheat oven to 350* F. Line a large baking tray with parchment paper.
Place 8 chilled cookie dough balls onto the prepared baking tray and bake for 11 to 12 minutes or just until lightly golden at the edges.
Allow the cookies to cool on the baking tray for 5 minutes before transferring them to a cooling rack to cool completely on the counter.
Repeat steps 7 & 8 until all the chewy sugar cookies have been baked.