Preheat oven to 400°F. Line two sheet pans (or cookie sheet) with parchment paper or grease the pans with a non-stick spray.
In a large bowl, whisk together the dry ingredients flour, cornstarch, and baking soda set the bowl aside.
Add the butter and sugar to the bowl of your electric mixer. Beat on medium-high speed for about 4 minutes until the butter is light and fluffy. Turn the speed down to low and add in the eggs one at a time, making sure each egg gets incorporated. Slowly pour the flour mixture into the mixture and blend just until combined.
Using a cookie scoop, scoop about one tablespoon worth of dough, roll the dough into balls, and slightly flatten the balls with your hand or rolling pin.
Pour the sprinkles into a plate. Press the cookies into the sprinkles making sure to coat all sides.
Stagger the cookies on the sheet pan, making sure you leave a gap between the cookies.
Bake cookies for 8- 11 minutes until the bottoms are golden brown. Allow them to cool on the pan.