Wisk flour and baking soda in med bowl and set
aside. Heat oven to 375 degrees and line baking
sheets with parchment paper. Melt 1-1/4 lb
butter in large skillet over med-high heat.
Cook, swirling pan constantly until butter is
dark golden brown and has nutty aroma. Transfer
browned butter to large heatproof bowl. Add
remaining 1/2 lb butter and stir to completely
melted. Add brown sugar, granulate sugar,
vanilla, and salt to melted butter; whisk until
fully incorporated. Add eggs and yolks; whisk
until mixture is smooth with no sugar lumps
remaining, abt 30 seconds or more. Let mixture
stand for 3 minutes, then whisk for 30 seconds.
Repeat process of resting and whisking two more
times until mixture is thick, smooth and shiny.
Using rubber spatula, stir in flour mixture
until just combine, about 2 minutes. Stir in
chocolate chips and nuts if using. Give dough
final stir to ensure no flour pockets remain
and ingredients are evenly distributed.
Roll into balls and space them about 2 inches a
part on baking sheets. Bake until cookies are
golden brown, still puffy, and edges have begun
to set but centers are soft - 10 to 14 minutes,
rotating sheet half way through baking period.
Let cookies cool completely on sheets on wire
racks before serving.