1. Melt the butter in an aluminum, stainless, or silver colored pan. (A light colored pan helps you monitor the color of the butter to prevent burning.) Stir while butter bubbles and begins to turn brown. Remove from heat the instant you see it begin to become golden brown. Do not let it burn!
2. Preheat the oven to 350°. Add the brown butter to a large mixing bowl. Stir in the sugar, brown sugar, milk, and vanilla. As it cools mix in the eggs and yolks.
3. In a separate bowl combine the flour, salt, soda and cinnamon.
4. Once the wet mixture has cooled completely, add in the flour mixture and stir to combine.
5. Mix in the chocolate chips and the crumbled walnuts.
6. Scoop out 1/4 of the dough onto a large piece of plastic wrap. Form a flat loaf and repeat with the rest of the dough. Place in refrigerator to chill or in ziplock bag to freeze for baking later.
7. Once the dough has chilled, remove from refrigerator one pack at a time and form into tablespoon sized dough balls.
8. Bake on a parchment or silpat lined baking sheet at 350° for 8-10 minutes.
9. As soon as the cookies come out of the oven, sprinkle with Maldon sea salt and press it lightly into the cookie surface.
10. Remove from cookie sheet and let cool on rack or newspaper.