In the bowl of a stand mixer, cream together butter and sugars and light and creamy.
Add eggs, one at a time, mixing well after each one. Add vanilla extract and mix until incorporated.
In a large bowl, whisk together flours, cornstarch, baking soda, and salt. Pour into butter mixture and mix until just combined to avoid overmixing. Stir in chocolate chips/chunks.
Cover and refrigerate for at least an hour. Separate dough into balls and place on cookie sheet with parchment.
Preheat oven to 350°.
Bake for 12-15 minutes or until golden brown, you want the center to still be soft. Let them rest for at least 10 minutes to set. Place on a wire rack to cool.