Brown the butter by melting it in a small saucepan over medium heat, stirring frequently until golden brown with a nutty aroma, about 5–7 minutes.

In a large mixing bowl, combine the browned butter with brown sugar and granulated sugar, whisk until smooth. Add in the whole egg and egg yolk along with vanilla extract, mix well.

Whisk together all-purpose flour, baking soda, and salt in a separate bowl. Gradually add to the wet mixture, stirring gently until just combined.

Gently fold in chocolate chips or chopped chocolate using a spatula to evenly distribute.

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

Preheat your oven to 350°F (175°C) and prepare baking sheets with parchment paper.

Scoop tablespoon-sized balls of dough and place on baking sheets about 2 inches apart. Bake for 11–13 minutes until edges are set.

Cool cookies on the baking sheet for 5 minutes before transferring to a wire rack.