Preheat oven to 375°F. Line cookie sheets with silicone baking mats or parchment paper and set aside.

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 in three batches until just blended. Fold in the chips by hand. Cover and chill for at leadt 2 hours, but overnight for best results.

Take out the cookie dough and let sit at room temperature for 10 minutes.

Roll 2 tablespoons of dough into a ball that is slightly taller than wide and place onto the prepared cookie sheets, about 2 inches apart.

Bake for 8 minutes or until edges are barely golden (will look underbaked). Cool on baking sheets for 10 minutes before transferring to wire racks to cool completely. Store at room temperature kn an airtight container.