1. Preheat oven to 350 degrees. Line a cookie sheet with parchment paper or Silpat mat. Set cookie sheet aside.In a mixing bowl beat the butter and sugars on medium speed for several minutes until mixture becomes light and fluffy .2.Turn mixer to low and beat in the eggs and vanilla. Stop mixer, scrape bowl, then turn mixer to low speed and slowly add in the flour, cornstarch, baking powder, baking soda, and salt, stirring until mixture is combined. 3. Fold in the chocolate chips. (Note: for a truly authentic bakery style cookie you must use Guittard chips. I saw them make a batch and they plopped a whole box of Guittard chips on the counter to mix into the dough).Take ¼ cup of cookie dough and form into a ball, then place on cookie sheet leaving several inches of space for cookies to spread.4. Bake at 350 degrees for 15-20 minutes, or until cookies are lightly browned and edges are cooked.Remove cookies from oven and allow them to cool for several minutes on the cookie sheet before moving to a cooling rack to finish cooling completely. If you can wait that long. We highly suggest eating these cookies warm from the oven.*You may need to add a couple of tablespoons of water to the mixture if too dry.
Notes
Storing
Once baked, you can eat them straight out of the oven hot and ready. You can also put them in an airtight container for several days or freeze in a freezer container for about a month.
Reheating
If you are looking to make your cookies nice and hot and fresh again, just place them in the microwave for 10-20 seconds. I would say about ten seconds for room temperature cookies and twenty seconds (possibly thirty seconds) if frozen.