In a large mixing bowl, whisk together the relatively cooled brown butter, brown sugar, and granulated sugar until smooth and glossy. Add the eggs, vanilla extract. Whisk until fully combined.
Add the flour, corn starch, bread flour, baking soda, baking powder, and salt. Briefly stir together on top before mixing into the butter mixture. Fold together until just combined. Avoid over mixing.
Fold in the chocolate chunks, reserving a handful for topping.
Preheat the oven to 180°C (350°F) conventional or 170°C (340°F) fan-forced. Line your baking tray with parchment paper.
Portion the dough into large cookie scoops, about 55–60g each. Place them 2–3 inches apart on the prepared trays.
Press a few extra chocolate chunks onto the tops of each dough ball. Bake for 10–12 minutes, or until the edges are golden brown and the centers still look slightly underbaked.
Let them cool on the baking tray for a couple of minutes before transferring to a wire rack using a metal spatula, top with flaky sea salt and add more chocolate on the cookie if your heart desires.