In a saucepan heat butter over medium heat, stirring constantly until the butter begins to foam and turns a golden brown color. Take the butter off the heat and allow to cool completely.
In a large mixing bowl, combine the (cooled) brown butter, brown sugar and granulated sugar, whisk until combined.
Add the egg, egg yolk and vanilla extract. Mix well.
Add the flour, baking soda and sea salt, folding until just combined . Don't over-mix! Carefully fold in the chocolate.
Scoop dough into balls onto a baking sheet (2 inches apart) and place in the refrigerator for 20-30 minutes to cool.
Preheat your oven to 325 degrees.
Once the dough is cooled, bake for 12-14 minutes on a baking sheet lined with parchment paper until the edges are golden brown.
Remove from oven and allow to cool on a baking rack for 20 minutes before serving.
Serve with a tall glass of ice cold milk and enjoy!