Preheat oven to 350 degrees. Line 2 baking sheets with parchment paper or a silicon baking mat.
In a stand mixer with the paddle attachment cream butter until light and fluffy, 1-2 minutes.
Add in sugar and cream for an additional 1-2 minutes or until combined.
Add in the egg and vanilla until combined and scrape down the sides of the bowl.
In a large bowl combine flour, cornstarch, baking soda and salt.
In two additions add the dry ingredients.
Fold in chocolate chips by hand.
Scoop tablespoon sized cookies onto the prepared baking sheets.
Bake for 10 - 11 minutes or until the cookies are golden brown, they may still be a little underdone in the middle that is fine, they will continue to cook on the baking sheet.
Allow the cookies to cool for 5 minutes on the baking sheet then transfer to a wire rack to cool completely.