Preheat oven to 375℉/190℃.
Spray 4 six-inch cast iron skillets with cooking spray. Set aside.
In a small bowl, sift together flour, baking soda, and salt. Set aside.
In the bowl of an electric mixer, combine butter and sugars.
Beat until well combined.
Add eggs one at a time, beating well after each addition.
Mix in vanilla.
Stir in flour mixture.
Add chocolate chips and walnuts.
Stir to mix.
Put 1 cup of cookie batter into each of the prepared pans.
Press to fill whole pan.
Bake 10-12 minutes, or until done.