Preheat oven to 350 degrees. Spray a 9x13 glass baking dish with cooking spray. Set aside.
In a large bowl, using an electric mixer or a stand mixer fitted with the paddle attachment, cream together butter and sugar.
In a separate bowl sift flour, baking soda and salt.
Pour into prepared 9x13 baking dish. Bake for 30-35 minutes or until it passes the toothpick test.
For the cream cheese frosting, beat cream cheese until fluffy and smooth. Add in milk, vanilla and powdered sugar, continuing to mix.
When cake has cooled, frost with cream cheese frosting. Top with chopped walnuts.
If you've tried this recipe, come back and let us know how it was!