In a medium saucepan over medium heat, melt the unsalted butter. Continue to cook, stirring often, until the butter turns golden brown and emits a nutty aroma, about 5-7 minutes. Remove from heat and let cool slightly.

In a large bowl, combine the brown sugar and granulated sugar. Pour in the warm browned butter and mix until well combined.

Beat in the large egg and vanilla extract until the mixture is smooth and creamy.

In another bowl, whisk together the all-purpose flour, baking soda, and salt.

Gradually add the dry ingredients to the wet mixture, stirring just until combined. Be careful not to overmix! Fold in the chopped pecans.

Cover the dough and chill in the refrigerator for at least 30 minutes.

Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.

Using a cookie scoop or spoon, drop tablespoon-sized balls of dough onto the prepared baking sheet, leaving space between each cookie. Bake for 10-12 minutes or until the edges are lightly golden.

Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.