Whisk the flour, cornstarch, baking soda, and salt in a medium bowl until combined.
Mix the melted butter, brown sugar, and granulated sugar in a large bowl until fully smooth.
Beat in the eggs and vanilla extract until the mixture is pale and glossy.
Fold the dry ingredients into the wet mixture until only a few streaks of flour remain.
Incorporate the chocolate chunks manually into the thick dough.
Refrigerate the dough for at least two hours for hydration and flavor development.
Preheat your oven to 350 degrees Fahrenheit.
Line a baking sheet with parchment paper.
Scoop dough into balls and place on the sheet.
Bake for 12 minutes until the edges are golden and the centers are soft.