Preheat oven to 350°F and line baking sheets with parchment paper or silicon mats.
In a medium bowl, whisk together the flour, cornstarch, baking soda, and salt.
In the bowl of a stand mixer fitted with the paddle attachment, cream the butter and both sugars together on high until light and fluffy.
Add in the eggs one at a time, incorporating fully after each addition.
Add in the vanilla extract. Scrap down the bottom and sides of the bowl if needed and beat on medium high, ensuring the ingredients are completely mixed together.
Turn the mixer to low and slowly add in the dry ingredients. Be careful not to over mix!
Fold in the chocolate chunks or chips.
Roll the dough into balls and bake for about 9-11 minutes. If desired, place some extra chocolate chunks or chips onto the tops of the warm cookies.
Let the cookies cool on the baking sheet about 5 minutes. Then, transfer them to a wire rack to cool completely.