In a bowl, sift together the flour, baking soda and salt. In another bowl, cream together the melted butter, brown sugar and white sugar until blended. Add the vanilla, egg, and egg yolk until light and creamy. Add the sifted ingredients until just blended and then stir in the chocolate chips.
Refrigerate the dough for at least an hour. Preheat the oven to 325. Drop dough a spoonful at a time onto the prepared cookie sheet about 3 inches apart. Make the size to your liking. Bake for 15 to 17 minutes until the edges are lightly toasted. Turn half-way through and cool on baking sheets for a few minutes before transferring to wire racks to cool completely.