Sift together the flour, baking soda and salt; set aside.
In a medium bowl, cream together the melted butter, brown sugar and white sugar until well blended. Beat in the vanilla, egg, and egg yolk until light and creamy. Mix in the sifted ingredients until just blended. Stir in the chocolate chips by hand using a wooden spoon.
Drop cookie dough scoops on a baking sheet close enough together you can fit them all on at once. Place in freezer for about an hour. Remove from freezer, bag up and throw them back in the freezer until ready to bake.
When ready to bake, preheat the oven to 325 degrees F (165 degrees C). Grease cookie sheets or line with parchment paper.
Bake for 9-12 minutes in the preheated oven, or until the edges are lightly toasted. Cool on baking sheets for a few minutes before transferring to wire racks to cool completely.
Altitude Adjustments: I am in Utah at about 5500 feet above sea level. if you are at a lower altitude decrease the flour by 1 to 2 tablespoons. At a higher altitude (6000 and above), add a few tablespoons flour and take away one of the sugar.