Using your stand mixer or bowl, add the ROOM TEMPERATURE melted butter (or soft butter) and both sugars and mix until creamed for about 2-4 minutes Add in your eggs. Mix until incorporated then add your vanilla and mix again until incorporated.

Using a separate bowl, add flour, cornstarch, salt and baking powder and mix until combined. Then add this dry ingredient mix to your wet mix and mix until all your flour is incorporated. Add your chips and mix until combined.