Grease cookie sheets or line with parchment paper (I actually did neither, and they came out fine on a plain old bare shiny metal cookie sheet).
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 dry ingredients until just blended
Stir in the chocolate chips, then chill in the fridge for 1-2 hours
Drop cookie dough 1/4 cup at a time onto the prepared cookie sheets (I did large golf ball size chunks, and could fit 9 at a time - they spread quite a bit, so don't try to cram them)
Cookies should be about 3 inches apart
Bake for 10-12 minutes in a 325 F 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
For a softer cookie be careful not to overcook- remove cookies from oven when the edges are barely toasted
For a crunchier cookie, bake for 12-15 minutes or until edges are golden brown