In a medium skillet or saucepan, melt 1 cup of butter over medium heat. Swirl frequently as it foams and crackles. After 4-5 minutes, golden-brown specks will form at the bottom with an irresistible nutty aroma. Immediately remove from heat and transfer to a heat-safe bowl to cool for 20 minutes.

In the warm pan, quickly toast the chopped pecans for 2-3 minutes in residual heat until fragrant. Let cool.

In a medium bowl, whisk together all-purpose flour, baking soda, fine sea salt, and ground cinnamon. Set aside.

In a large bowl, whisk the cooled brown butter, dark brown sugar, and granulated sugar vigorously for 2 minutes until glossy and smooth. Whisk in eggs one at a time, followed by pure vanilla bean paste.

Fold in the dry flour mixture using a rubber spatula just until combined (do not overmix). Gently fold in the toasted chopped pecans.

Cover dough with plastic wrap and chill in the refrigerator for at least 45-60 minutes (this allows the flour to hydrate and deepens the toffee brown butter notes).

Preheat oven to 350°F (175°C). Line two large baking sheets with parchment paper.

Scoop dough using a 3-tablespoon cookie scoop onto baking sheets, placing them 2 inches apart. Press a few extra toasted pecan halves gently into the tops of each dough ball.

Bake for 10-12 minutes until the edges are golden-brown and set, while the centers remain soft and slightly puffy. Immediately sprinkle with flaky sea salt and let cool on the pan for 10 minutes before transferring to a wire rack.