In a standing mixer combine the room temperature butter and granulated sugar, mix until combined and then turn the speed up to high and whip for 1-2 minutes until the mixture is lighter in color and texture
Turn the mixer off and add the eggs and vanilla extract to the mixer. Turn it back on low speed and mix until combined.
Turn the mixer off and add the cocoa powder, flour, salt, baking soda, and cornstarch. Mix on low until combined.
Pour the bag of semi sweet chocolate chips into the batter and fold in.
Pour and spread the batter into a greased and parchment paper lined 9x13 pan
Bake the brownies for 35-37 minutes until the top of the brownies are no longer shiny in the center of the pan.
Remove the brownies and allow them to cool. Enjoy!