Brown the Butter: Melt butter in a stainless steel skillet over medium heat. Swirl occasionally for 4 to 5 minutes as it foams, crackles, and turns deep golden amber with nutty brown flecks at the bottom. Pour into a heatproof bowl and let cool for 10 minutes.

Toast the Pecans: In the same hot skillet off heat (or over low heat), toast chopped pecans for 2 to 3 minutes until aromatic and fragrant. Set aside to cool.

Whisk Sugars & Eggs: Whisk cooled brown butter with dark brown sugar and granulated sugar for 2 minutes until glossy and smooth. Beat in eggs one at a time, followed by vanilla paste, whisking vigorously for 1 minute until batter thickens slightly.

Fold Dry Ingredients: Fold in all-purpose flour, baking soda, and fine sea salt using a rubber spatula just until combined (do not overmix). Gently fold in toasted pecans and chopped dark chocolate chunks.

Scoop & Chill: Use a large 3-tablespoon cookie scoop to portion dough into 14 balls onto a tray. Chill dough in the refrigerator for 20 minutes (or bake right away for slightly wider spread).

Bake & Ripple: Preheat oven to 350°F (175°C). Space dough balls 3 inches apart on parchment-lined baking sheets. Bake for 9 to 11 minutes until edges are set and golden but centers remain soft. Immediately bang the pan lightly on counter for bakery ripples, sprinkle with flaky sea salt, and cool on wire rack.