In a stand mixer cream butter and both sugars together until light and fluffy, about 2 minutes. Mix in the egg and vanilla. Add flour, cornstarch, baking soda and salt. Mix until everything is combined. Fold in the chocolate chips.
Mix in the egg and vanilla and blend until the egg is fully incorporated.
Add flour, cornstarch, baking soda and salt and mix until everything is just combined. Fold in the chocolate chips until evenly incorporated.
Scoop golf ball size balls of dough onto a baking sheet. Chill the dough for 30 minutes. The longer you chill the thicker and more developed the taste will be of the cookies.
Preheat oven to 350º F.
Bake for 9-11 minutes, until the edge are just golden brown. The center will appear dry but still a little underdone.
Let cookies cool for 5 minutes before removing to a wire rack to cool completely.
