Preheat oven to 325 degrees F. Line a baking sheet with parchment paper.
In a medium bowl whisk together the flour, cornstarch, and kosher salt. Set aside.
2 cups All-purpose flour, 2 tbsp Cornstarch, 1/2 tsp Kosher salt
In the bowl of a stand mixer combine the butter and powdered sugar. Beat on medium-high speed until lightened in color and fluffy, about 5 minutes. Add the vanilla extract and stir in until combined. Scrape down the bowl as needed.
1 cup Unsalted butter, 3/4 cup Powdered sugar, 1 tsp Vanilla extract
Turn the mixer to medium-low and gradually add the dry ingredient mixture until just combined.
Lightly dust your hands with powdered sugar. Using a tablespoon cookie scoop roll the dough into balls. Place them 1 to 2 inches apart on the prepared baking sheet. Use the tines of a fork to slightly flatten the dough balls. Sprinkle with nonpareils, jimmies, or colored sugar, if desired.
Sprinkles
Bake for 12-15 minutes just until the bottom of the cookies start to tan. Allow to cool completely on the baking sheet.