Step 1

Adjust oven rack to middle position and heat oven to 375F/190C degrees. Line 2 large baking sheets with parchment paper or silicon mats.

Step 2

In a medium bowl, whisk together the flour and baking soda; set aside.

Step 3

In a light-colored skillet, heat 10 tablespoons (5 oz/ 142g) of the butter over medium-high heat until melted, about 2 minutes. Continue cooking, stirring and scraping the pan constantly with a heatproof rubber spatula until the butter turns dark golden brown and has a nutty, caramel-y aroma, 1 to 3 minutes. Be careful not to burn it.

Step 4

Remove the skillet from the heat and, using the spatula, transfer the browned butter to large heatproof bowl. Whisk remaining 4 tablespoons (2 oz/ 58g) of butter into the browned butter until completely melted.

Step 5

Whisk in both sugars, salt, and vanilla to the bowl with butter until fully incorporated.

Step 6

Add in the egg and yolk and whisk until mixture is smooth and emulsified with no sugar lumps remaining, about 30 seconds. Let mixture rest for 3 minutes, then whisk for another 30 seconds. Repeat the process of resting and whisking 2 more times (a total of 4 whisks, 3 rests) until mixture is thick, smooth, and slightly lightened in color.

Step 7

Using a rubber spatula, stir in the flour mixture until just combined. Do not overmix; a few streaks of flour is OK.

Step 8

Stir in chocolate chips and nuts (if using), giving the dough a final stir to ensure that no flour pockets remain.

Step 9

Portion the dough into 16 equal scoops, each about 3 tablespoons, about 2 1/4oz/ 64g (or use #24 cookie scoop). If the dough feel too soft or warm to scoop, cover and refrigerate for about 1/2 an hour until scoopable.

Step 10

For thicker cookies, shape each dough scoop into an oblong ball. Then press a few chocolate chips on each top for looks. You could bake right away, if you prefer, with great results, but I've found that chilling the dough for at least 2 hours or up to 5 days produces even thicker cookies. I like to let them chill overnight arranged in a baking sheet and covered with plastic wrap, but I also happen to make extra and freeze them for up to one month. (*see note below for freezing cookies)

Step 11

When ready to bake, arrange dough balls, 2 inches apart on the prepared baking sheets, 8 dough balls per sheet. (Smaller baking sheets can be used, but will require 3 batches.)

Step 12

Bake cookies one sheet at a time until cookies are golden brown, flattened but still puffy, and edges have begun to set but centers are still soft but no longer wet, 10 to 13 minutes, rotating baking sheet halfway through for even baking. Set the timer to 10 minutes to check for doneness, then add 1 minute at a time if needed. Do NOT overbake or they'll end up hard instead of soft and chewy. A trick to know that they're done, is to lift the edge of the cookie with your finger, if it lifts, then they're done, if its still too soft to lift then give it another minute or so. The cookies will continue to cook from the residual heat of the baking sheets as they cool.

Step 13

Transfer baking sheet to wire rack and let the cookies cool completely on the baking sheets, at least 20 minutes. Resist the urge to eat them right away or they'll taste raw and undone. Once completely cooled, store in an airtight container to maintain their softness.