Preheat the oven to 325'F (165'C). Grease cookie sheets or line with parchment paper.
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 about 1 tablespoon at a time onto the prepared cookie sheets.
Cookies should be a few inches apart, as they will expand during baking.
Bake for about 15 minutes, or until the edges are lightly toasted, in the preheated oven.
Cool on baking sheet for a few minutes.
Transfer to wire rack to cool completely.
...and there you go, fat chocolate chip cookies! Enjoy with a cold glass of milk!