Preheat your oven to 350℉ and spray a 9x13 pan with baking spray. Set the pan aside.
Add the butter and light brown sugar to the bowl of a stand mixer and beat with the paddle attachment until it is light and fluffy. You can also use a large bowl and electric mixer. Remember to scrape down the sides of the bowl so that all of the butter is blended in well.
1 cup unsalted butter, 1 ½ cups light brown sugar
Add the eggs one at a time, beating after each addition.
Mix in the vanilla.
1 ½ teaspoons vanilla extract
Add the flour, baking soda and salt. Mix slowly as the batter will be very thick. Sometimes I use my hands at the end to make sure everything is really well blended and the batter is smooth.
2 ¼ cup flour, 1 teaspoon baking soda, ¾ teaspoon salt
Mix in 1 ½ cups of the chocolate chips and nuts, stirring them in slowly.
2 cups chocolate chips, 1 cup coarsely chopped walnuts
Dump the cookie dough into the greased pan and use your hands to press it into the pan, making and even layer.
Sprinkle the remaining ½ cup of chocolate chips over the top of the top of the dough in the pan then gently press the chips into the dough.
Bake the bars for about 22-25 minutes. The top of the cookie bars and the edges will be golden brown but the bars will still be a little soft to the touch (this is good!).
Let the cookie bars cool to room temperature then cut and enjoy!