Prepare the brown butter - place a stick of salted butter in a small sauce pan over medium low heat. Allow the butter to melt completely. Whisk occasionally until the top of the melted butter looks foamy. Once it looks foamy, whisk constantly until you start to see small brown flecks at the bottom of the pan and immediately remove from heat.

Allow the browned butter to cool completely. I like to place it in the fridge for 15 minutes.

Pour the cooled brown butter into a large bowl - be sure to scrape in all of those browned bits with a spatula. Add the brown sugar and granulated sugar to the bowl.

Mix them together with an electric hand mixer or paddle attachment of a stand mixer until evenly combined. Add the egg and vanilla to the bowl and mix until light and fluffy.

Pour the all purpose flour into the mixing bowl along with the baking soda and mix again with the electric mixer until a smooth dough forms. Fold the chocolate chunks in with a flat spatula.

Cover the bowl and place in the refrigerator. Chill for at least 30 minutes.

Preheat oven to 325F and line a baking sheet with parchment paper. Scoop out 2 tbsp of dough for each cookie and roll into a ball. Place 9 dough balls at a time on the baking sheet and press down lightly. Top with flakey sea salt.

Bake at 325F for 12-14 minutes. Allow to cool for at least 5 minutes on the cookie sheet and then transfer to a wire cooling rack to finish cooling. 

** To bake from frozen: Roll into balls and freeze. Bake directly from frozen at 325F for 16 minutes.