1. Cut butter into pieces and melt in a light-colored saucepan over medium heat, swirling occasionally until milk solids turn golden brown and smell nutty (about 5-7 minutes). Pour into a heatproof bowl and let cool for 15 minutes.

2. In a large mixing bowl, beat cooled brown butter with both sugars for 2-3 minutes until well combined.

3. Add eggs one at a time, beating well after each addition. Mix in vanilla extract until smooth and glossy.

4. In a separate bowl, whisk together flour, baking soda, and salt.

5. Add dry ingredients to wet ingredients, mixing just until no flour streaks remain. Do not overmix.

6. Fold in chocolate chips and chunks with a spatula until evenly distributed.

7. Cover bowl with plastic wrap and refrigerate for at least 2 hours, preferably overnight (8-24 hours).

8. When ready to bake, preheat oven to 350°F (175°C). Line baking sheets with parchment paper.

9. Scoop dough using a 3-tablespoon cookie scoop, roll briefly into balls, and place on prepared sheets 3 inches apart.

10. Optional: Gently pull each dough ball in half, then press back together with torn sides facing up for craggy tops.

11. Sprinkle tops lightly with flaky sea salt if desired.

12. Bake for 11-13 minutes, rotating pans halfway through, until edges are golden but centers still look slightly underdone.

13. Let cookies rest on baking sheet for 5 minutes, then transfer to a cooling rack.