browned butter chocolate chip cookies

makes 16
1 3/4 cups all purpose flour
1/2 tsp baking soda
14 tbs unsalted butter--divided
1/2 cup granulated sugar
3/4 cup dark brown sugar-firmly packed
1 tsp kosher salt
2 tsp vanilla extract
1 large egg
1 large egg yolk
1 1/4 cup bittersweet chocolate chips
3/4 cups walnut halves

heat oven to 375F. line baking sheets with parchment paper. whisk flour and baking soda in a bowl and set aside. heat 10 tbs of butter in a skillet over medium heat, swirling continually, until it becomes a dark golden brown and it smells a bit toffee like. this should take about 3-5 minutes...the larger the skillet, the quicker the reaction. remove from heat and pour butter into mixing bowl. add the remaining butter and stir until it is melted. add the sugars, salt and vanilla to the bowl and hand-whisk until mixed well. add egg and egg yolk and whisk until smooth and begins to lighten in color a bit. let rest for 3 minutes. whisk again for 30 seconds and let rest for 3 minutes. do this procedure 2 more times. use a wooden spoon or spatula to stir in the flour mixture so that it is just combined = don't over-mix. stir in chocolate and nuts. scoop out large balls (about 3 tbs) onto to the parchment, placing about 2" apart. Bake for about 10-14 minutes or until the edges are slightly browned. cool on wire rack.