• Preheat the oven to 350° F.
• Line a baking sheet with parchment paper and set aside.

For the Brown Butter

• Melt butter in a medium sauce pan on medium heat. Stir the butter to make sure it melts evenly. Once the butter is completely melted, it will start to foam up. Continue stirring the butter. As it cooks, it will start to change into a deeper color. This could take 6-8 minutes.
• You'll start to notice a nutty aroma and the butter will begin to have brown specs at the bottom of the pan. Continue stirring and remove from the heat and pour into a heat-proof bowl, then stir in the espresso powder, and let cool slightly before continuing with recipe. The entire process of browning butter from start to finish should not take more than 10 minutes on medium heat.

For the Cookies

• In a separate bowl, Add flour, salt, and baking soda, whisk then set aside.
• Once brown butter is slightly cooled, add the sugars (both brown and granulated) into the bowl of the brown butter, and mix with a spatula. Add the egg + egg yolk and vanilla extract and stir until combined.
• Slowly add the dry ingredients and mix until just combined. Add the chocolate mix.
• Scoop cookie dough using a large cookie scoop (I use 3 tablespoon cookie scoop). Place on baking sheet, making sure to spread them apart at least 2".
• Optional: Chill the dough in the fridge for 30 minutes (up to 72 hours)- this will help develop more flavor, and reduce spreading.
• Bake for 10 minutes, then remove from the oven. Let cool for a few minutes on baking sheet and then transfer to cooling rack.
• Sprinkle with sea salt and enjoy.