Preheat the oven to 350 degrees F. Line two baking sheets with parchment paper and set them aside.

In a medium-sized bowl, whisk together the flour, cornstarch, baking soda, and salt. Set aside.

In the bowl of a stand mixer, cream the butter and cream cheese together until they are smooth.

Add the sugars, egg, and vanilla extract and cream together for 4-5 minutes, or until the mixture is light and fluffy.

In a couple of batches, add the dry ingredients to the wet. Mix until they just come together, scraping the sides of the bowl as necessary. Fold in the chocolate chips.

Using a cookie scoop, drop the dough onto the prepared baking sheets. Press the tops down lightly with your hand, press in a few extra chocolate chips, and top with a sprinkling of sea salt.

Bake 8-10 minutes, or just until the tops appear to be dry. They will continue to firm up as they cool. 

Allow the cookies to cool for 5-7 minutes on the cookie sheet before removing them to a wire rack to finish cooling completely.