Preheat the oven to 400 degrees.
Cut your butter into slices.
Place butter slices into a large mixing bowl and beat with mixer (stand mixer is preferred if you have it - use the paddle attachment) until it starts to smooth.
Add in the sugars and beat for about 1-2 minutes until smooth.
Add in the eggs and beat until just incorporated.
Dump in the flour, cornstarch, baking soda, baking powder, and salt.
Mix on low speed until the wet and dry ingredients are combined.
Pour in the chocolate chips and pulse the mixture 7 or 8 times until they are mixed evenly throughout the batter.
Measure out the batter to be 3 to 3.5 oz, grabbing and placing the dough with your hands. Don't pack it or roll the dough into a tight ball.
Place 6 cookies per cookie sheet. (A silicone liner works great)
Place in the oven to bake for about 8 minutes, or until the cookie top and bottom are golden.
Allow the cookies to rest on the pan for about 10 minutes. (I know you'll want to bite into them sooner, but be patient or the cookie will fall apart.)
Store cookies in an airtight container, or ziplock bag for 1-2 days.