2 cups (8.88 0z) all purpose flour
3/4 tsp baking soda
1/2 tsp baking powder
1 tsp salt
1 1/2 sticks unsalted butter
1/2 cup (3.6 oz) granulated sugar
3/4 cup (6.5 oz) packed brown sugar
2 tsp vanilla extract
1 large egg
1 large egg yolk
1 1/4 cup semi sweet chocolate chips
1/2 cup chopped walnuts (optional)
Whisk flour, baking soda and salt together in a bowl and set aside.
In a small bowl crack one egg into it. Add just the yolk of the second egg. Then add the 2 tsp of vanilla in with the eggs. Set aside.
In another bowl, mix the sugars together.
Heat 1 1/4 stick of the butter in a skillet over medium heat. Place the rest of the unmelted 1/4 cup of butter in another bowl. Melt the butter in the skillet slowly making sure not to burn in. Swirl the butter often and notice that it will become foamy and then begin to darken in color a bit, 3-4 minutes. You should begin to notice a nutty smell. When this happens, remove it from the heat and add it to the bowl with the unmelted butter.
Swirl the butter in the bowl until the unmelted portion has melted then add the sugars and mix until smooth. Add the eggs and vanilla. Mix with a whisk for 30 seconds then let the mixture rest for 3 minutes. Repeat 2 more times.
Now with a spatula, mix in the flour mixture gradually into the sugar bowl until incorporated. Then add the chocolate chips and nuts if using.
Refrigerate the cookie dough for at least an hour before baking.
Heat oven to 375 degrees and place rack in the center of the oven.
Line a cookie sheet with parchment paper.
Make cookies larger than what you may normally would, about 10-12 to a tray. Cook one tray at a time for 12-14 minutes. They should still be somewhat soft to the touch when you take them out. Cool cookies on a rack.