Heat oven to 375 degrees. Line 2 large baking sheets with parchment paper.
Whisk flour and baking soda together in medium bowl; set aside.
Heat 10 tablespoons butter in skillet (preferably non-stick, but dance with those that brung ya) over medium-high heat until melted, about 2 minutes. Continue cooking, swirling pan constantly until butter is dark golden brown and has nutty aroma, 1 to 3 minutes. Remove skillet from heat and, using heatproof spatula, transfer browned butter to large heatproof bowl. Stir remaining 4 tablespoons butter into hot butter until completely melted.
Add both sugars, salt, and vanilla to bowl with butter and whisk until fully incorporated.
Add egg and yolk and whisk until mixture is smooth with no sugar lumps remaining, about 30 seconds. Let mixture stand 3 minutes, then whisk for 30 seconds.
Repeat process of resting and whisking 2 more times until mixture is thick, smooth, and shiny. You will definitely lose track of how often you've done this - more cycles is fine. Just keep cleaning up the kitchen while it rests and for Pete's sake, use a timer!
Using rubber spatula or wooden spoon, stir in flour mixture until just combined, about 1 minute. Stir in chocolate chips and give the dough a final stir to ensure no flour pockets remain.
Dough onto sheets
Bake 'em 10-14 min.