In a saucepan over medium heat melt the first 2oz of butter, watch carefully and mix constantly. This is browned butter, take it off before it becomes burnt butter.
In a large bowl mix add the brown butter and the regular butter, mix until the butter is all combined. Add the brown sugar and granulated mix and beat for 1 minute.
Add in egg, egg yolk, and vanilla extract beat for two minutes. After the two minutes let the batter rest for 30 seconds mix for another minute to two minutes.
Slowly add flour mixture to the wet ingredients, mixing just until combined then stir in the chocolate chips. Place dough covered in the fridge for 30 minutes to an hour.
Scoop 2 tablespoons balls of dough and bake for 10-12 minutes, the cookies should be just, they will cook a little bit more on the tray while they cool.