Line a baking sheet with a nonstick baking mat or parchment paper and set aside.
In a stand mixer cream the butter, light brown sugar, and sugar together until creamy. Then add in the eggs and vanilla and beat for another 20 or so seconds until combined. Set aside.
In a large bowl mix the flour, cornstarch, baking soda, and baking powder. Set aside.
Add the dry ingredients to the butter mixture and mix until just combined, do not overmix.
Fold in the chocolate chips and chocolate chunks using a rubber spatula.
Use a small cookie scoop and place 8-10 cookies on the baking sheet and bake for 9-10 minutes. We like to add extra chocolate chips to the top before baking.
Place a towel on the counter and then remove the baking sheet from the oven. Carefully drop the cookie sheet onto the towel. Let the cookies sit on the baking sheet for 2 minutes and then you can transfer to a cooling rack. This step is optional but we find it gives the cookies the best texture.
Remove cookies from the baking sheet and cool on a wire rack.
Dust with powdered sugar or sprinkle with Maldon sea salt if desired.
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Notes
9 minutes will give you more of a soft and chewy cookie, 11 minutes and after you'll get more of a crispy cookie.
Carefully dropping the cookie sheet onto a towel-lined counter after baking is our best cookie trick! After that, you can let the cookies sit on the baking sheet for 2 minutes, and then you can transfer them to a cooling rack. This step is optional but we find it gives the cookies the best texture. Be cautious doing this on a fragile counter. You can also allow the cookies to sink naturally on their own as they cool.
To ensure your oven is cooking at the correct temperature we suggest using an oven thermometer to check.
Add a few chocolate chips or chunks to the tops of the cookie dough balls before baking. This will make your cookies pretty when they come out and look full of chocolate chips on the top not just inside.