Preheat oven to 375 F.
In mixing bowl, beat the sugar and butter.Add the egg and the vanilla extract and beat until blended.
In separate bowl, sift flours, cornstarch, baking soda, salt amd add slowly to the butter mixture. Mix until blended. Stir in the chocolate chips until blended.
The dough will be on the dryer side, so you may have to form a ball with your hands. Place cookes a couple inches apart on baking sheet and bake at 375 F for about 10 minutes.