1. Melt 1/2 stick of butter (DO NOT MELT ALL THE BUTTER) in the microwave or in a small pot on the stove and allow to cool slightly. If using a microwave, use 50% power,  and keep a close eye on the butter. Start with 30 seconds, then check every 15-30 seconds. 
2. In a medium sized bowl, whisk together the all purpose flour, salt, and baking soda. 
3. Cream together the remaining butter (1 stick) and sugars on medium low speed for two to three minutes in a stand mixer fitted with the paddle attachment or in a medium sized bowl using a hand mixer. 
4. Next, mix in the melted butter. Do not overmix.
5. Add the eggs and egg yolk to the bowl one at a time, mixing in between each addition and scraping down the side of the bowl as needed with a rubber spatula.
6. Add the vanilla and mix until combined. 
7. Slowly mix in your dry ingredients a little at a time until completely incorporated.
8. Stir in the chocolate chips and chopped walnuts. 
9. Allow the cookie dough to cool in the refrigerator for at least an hour or up to 24 hours (the longer the better)

When ready to bake:

1. Preheat oven to 350 degrees F.
2. Use a medium cookie scoop and place your cookies on a baking sheet lined with parchment paper or a silicone baking mat.
3. I like to use the palm of my hand to flatten out the cookies slightly on the top. Just apply a small amount of pressure to flatten them just slightly.
4. Press a few extra chocolate chips into the top of each cookie to make them extra pretty. 
5. Bake one batch at a time (if possible) on the center rack for 13 minutes. Cookies may look slightly underdone at this point, but as long as they are set this is perfect! Under-baking them slightly keeps them soft for days!
6. Transfer cookies to a wire cooling rack to allow to cool completely.