Preheat your oven to 375 degrees F (190 degrees C) and line two baking sheets with parchment paper.
In a medium saucepan over medium heat, melt the butter. Continue to cook, swirling the pan occasionally, until the butter foams and turns a golden brown color with small brown bits at the bottom, which should take about 5 to 8 minutes. Immediately pour the brown butter into a large heatproof bowl to stop the cooking and let it cool for 15 minutes.
Add the brown sugar and granulated sugar to the slightly cooled brown butter. Use an electric mixer on medium speed to beat the mixture for 2 minutes until it is well combined and smooth. Beat in the eggs one at a time, followed by the vanilla extract, ensuring each is fully incorporated before adding the next.
In a separate bowl, whisk together the flour, baking soda, and salt. Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined and no streaks of flour remain. Use a spatula to fold in the chocolate chips and toasted pecans, if using.
Drop rounded 2-tablespoon-sized balls of dough onto the prepared baking sheets, spacing them about 2 inches apart to allow for spreading. Bake for 9 to 11 minutes, or until the edges are golden brown and the centers appear soft and slightly puffed.
Let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely. This rest time on the hot pan will help them set.