To Brown Butter: Place butter in large pot or deep skillet. Melt butter over medium-low heat. The butter will go through different phases. It will begin to melt and bubble. Take a wooden spoon or spatula and stir often and around the sides of the pan. Let the butter melt and watch for it to begin changing colors from a creamy yellow to a deep amber yellow. The butter will begin to foam and this is why it is important to stir often so you can see what is going on below the foam. Small brown bits will begin to form and that will be a signal that the butter is officially browned. Butter can burn quickly so watch carefully. It is better to pull off of the heat a little early instead of browning too long and risk burning it. Since you want the butter to chill quickly, pour it into a large bowl and place in the refrigerator. Use a spatula to get every bit of butter out of the pan. Let it chill in the refrigerator for about 40-60 minutes. Pour chilled butter into mixing bowl. Add brown sugar and sugar and cream for 4-5 minutes, scraping the sides of the bowl often. Add eggs and egg yolk, one at a time, beating for 30 seconds after each addition. Stir in vanilla. Add flour, baking soda, and salt. Stir just until combined, avoid overmixing. Stir in chocolate chips. If time allows, wrap cookie dough tightly and let chill in the refrigerator for at least one hour. If time allows, chill for 24-48 hours. Preheat oven to 385 degrees. Place parchment paper liners or Silpat liners on baking sheets. Roll balls of cookie dough and place on cookie sheet. Bake for 9-10 minutes or until edges starts to become a light golden color.