Preheat the oven to 325 degrees F (165 degrees C). Lightly grease cookie sheets or line with parchment paper or a silicone baking liner.
In a large bowl, sift together the flour, baking soda and salt; set aside.
In a medium bowl, cream together partially melted butter, brown sugar and white sugar until well blended.
Beat in vanilla, egg, and egg yolk until light and creamy.
Mix in the sifted ingredients until just blended. Gently fold in the chocolate chips by hand using a wooden spoon.
Drop cookie dough 1/4 cup (yes, these are BIG cookies) at a time onto the prepared cookie sheets. Cookies should be about 3 inches apart.
Bake for 10 to 14 minutes in the preheated oven, or until the edges are just starting to turn a golden brown.
Cool on baking sheets for a few minutes before transferring to wire racks to cool completely.