Step 1: Melt the butter in a medium saucepan over medium heat, whisking until it turns amber brown and smells nutty.
Step 2: Pour the brown butter into a bowl and let it cool for 10 minutes before mixing.
Step 3: Whisk the sugars into the cooled butter until no lumps remain.
Step 4: Add the eggs, bourbon, and vanilla, whisking until the mixture becomes glossy and thick.
Step 5: Fold in the flour, baking soda, and salt until just combined.
Step 6: Stir in the chocolate chunks.
Step 7: Chill the dough in the refrigerator for at least 2 hours.
Step 8: Preheat oven to 350°F and scoop dough into 2-tablespoon balls onto a lined baking sheet.
Step 9: Bake for 10-12 minutes until edges are set but centers are soft.
Step 10: Sprinkle with flaky sea salt and cool completely on a wire rack.