Place the butter in a light-colored saucepan over medium heat. As it melts, it will begin to foam. Swirl the pan occasionally. After 5-8 minutes, you will see golden brown specks form at the bottom and smell a nutty, irresistible aroma. Immediately remove it from the heat and pour it into a large heatproof mixing bowl (including all the brown bits). Let it cool for 10-15 minutes.
To the bowl with the cooled brown butter, add both the granulated sugar and brown sugar. Whisk vigorously until the mixture looks smooth and combined, about 1 minute. Add the eggs, one at a time, whisking well after each addition until the dough is glossy and smooth. Finally, whisk in the vanilla extract.
In a separate, medium bowl, whisk together the all-purpose flour, baking soda, and fine sea salt. This ensures the leavening and salt are evenly distributed throughout the dough.
Pour the dry ingredients into the wet ingredients. Using a rubber spatula, gently fold the mixture together. Stop mixing as soon as you no longer see streaks of flour overmixing will make the cookies tough. Fold in the chocolate chips and chopped chocolate, reserving a few chips to press onto the tops of the dough balls later.
For the thickest, most flavorful cookies, cover the bowl and refrigerate the dough for at least 30 minutes, or up to 72 hours. This allows the flavors to meld and prevents the cookies from spreading too thin.
When you are ready to bake, preheat your oven to 375°F (190°C). Line two large baking sheets with parchment paper.
Scoop the dough into generous balls, about 3 tablespoons (approx. 60g) each. Roll them gently between your palms they should be taller than they are wide. Place them on the prepared baking sheets, leaving about 3 inches (8 cm) of space between each for spreading. Gently press a few extra chocolate chips onto the top of each dough ball for a bakery-style look.
Bake one sheet at a time for 11-13 minutes. The edges should be beautifully golden brown, while the centers will still look slightly soft and puffy. They will continue to set up on the hot pan
Let the cookies cool on the baking sheet for 10-15 minutes. This step is crucial for the perfect chewy texture. After that, transfer them to a wire rack to cool completely, or enjoy one warm—you deserve it!