Toast the Pecans: Add the chopped pecans to a dry skillet over medium-low heat. Toast for 4 to 5 minutes, stirring frequently until fragrant and lightly deepened in color. Transfer to a plate to cool completely.

Brown the Butter: Melt the butter in a stainless steel saucepan over medium heat. Swirl occasionally as it melts, foams, and crackles. After 5 to 7 minutes, brown specks will form at the bottom with a rich nutty aroma. Immediately pour into a heatproof bowl and let cool for 15 minutes.

Cream Butter and Sugars: Add the brown sugar and granulated sugar to the browned butter. Whisk vigorously for 2 minutes until glossy and smooth. Whisk in the eggs one at a time, followed by the vanilla extract, until the mixture is pale and ribbon-like.

Fold Dry Ingredients: In a separate bowl, whisk together the flour, baking soda, and kosher salt. Fold the dry mixture into the wet dough with a spatula just until a few flour streaks remain.

Add Pecans & Chocolate: Gently fold in the toasted chopped pecans and dark chocolate chunks until evenly distributed. For best flavor and chew, chill the dough balls for 30 minutes in the refrigerator.

Bake to Chewy Perfection: Preheat oven to 350°F (175°C) and line two baking sheets with parchment paper. Scoop 3-tablespoon mounds of dough (approx. 55g each) 2 inches apart. Bake for 10 to 12 minutes until edges are golden and set, but centers are still soft and slightly underbaked. Remove from oven, sprinkle immediately with flaky sea salt, and let cool on the pan for 10 minutes before transferring to a wire rack!