In a large bowl or in the glass bowl of your stand mixer, melt the butter for 30-40 seconds or until it just barely melts. Add the light brown sugar and the white sugar and beat for 2 minutes until the mixture is fluffy and lightens in color. Add the vanilla and the egg, continue to mix until the egg incorporates. Add the egg yolk and mix.

Add the bread flour, baking soda, and salt on low speed and slowly mix until combined. The cookie dough will be thick. Stir in the chocolate chips.

Cover dough with plastic wrap and chill for 3-72 hours. This is a mandatory step for this recipe.

Remove the cookie dough from the refrigerator while the oven preheats (at least 10 minutes prior). Position two racks near the center of the oven, preheat the oven to 350ºF. Line two baking sheets with parchment paper or with silicone baking mats.

Using a medium cookie scoop, scoop the dough out into balls and place on the cookie sheet, about 12 per sheet. Bake the cookies for 10-12 minutes or until they just set in the middle. Let the cookies cool on the baking sheet for 10 minutes before transferring to a cooling rack. Cookies will be soft when fresh out of the oven but within 30 minutes they'll become chewy.