Place the butter in a small pot over medium heat. Let the butter melt and simmer, first it will foam up. Then the foam will subside.
Stir occasionally until the butter browns, it should have a nutty aroma. It should only take a few minutes.
You will notice brown specs on the bottom of the pan, and the butter will look lightly golden brown.
Immediately remove it from the heat. You should have about 1/2 cup of butter.
Add the chopped chocolate (or chocolate chips) to the butter.
Stir until the chocolate melts entirely.
Set it aside.
In a large bowl, add the eggs, the brown sugar, and the granulated sugar.
Beat the eggs and the sugar with an electric mixer on medium high for 5 minutes, until the mixture looks very light in color and fluffy.
Add the vanilla extract.
Now, pour the melted chocolate and brown butter in.
Mix on low until combined. Scrape the sides of the bowl.
Add the flour, cocoa powder, baking powder, and salt. It could be a good idea to sift the cocoa powder before adding it.
Mix on low.
You don’t have to stir until the mixture is completely incorporated. It’s ok to have some streaks of dry ingredients in the batter.
Add the chocolate chips, or chopped chocolate.
Fold with a spatula until combined.
Cover the batter with plastic. Place it in the fridge for 30 minutes at least. You could keep it in the fridge even overnight. If you keep it in the fridge overnight, remove it from the refrigerator about 10 minutes before scooping if it's too hard to scoop right away.
When you are ready to bake the cookies pre-heat the oven to 350ºF.
Scoop about 1.5 tbsp per cookie scoop, place on a baking sheet lined with silicone mat or parchment paper about 2 inches apart.
Scatter a few more chips on top of each cookie.
Bake the cookies in the pre-heated oven for about 10 to 12 minutes, until the cookies are set around the edges, they can be slightly undone in the center. The cookies will continue to set once they come out of the oven.
As soon as they come out of the oven, make sure to use a cookie cutter to make the cookies round by placing the cookie cutter around the cookie, and moving it in a circle motion, which should smooth the edges of the cookie and make it a perfect circle.
You can sprinkle some sea salt on top once they come out of the oven.
Let them cool down on a wire rack before serving.
Let the cookies cool down before serving.
Storage
Store the cookies in an air-tight container on the counter at room temperature for up to 3 days.
Notes
Espresso powder: add 1/2 tsp of espresso powder to the batter along with the flour and cocoa powder, for a deeper chocolate flavor.Brown butter: If you want to skip the brown butter, simply use 1/2 cup butter instead, and melt it directly with the chocolate instead of browning it first.Also important to note that you need 1/2 cup of butter for the recipe, so make sure to measure it once you remove the brown butter from the heat, to ensure there's 1/2 cup and not more, or less.