Beat cake mix, 1 egg, butter, and 2 teaspoons pumpkin pie spice on low with an electric mixer in a large bowl until crumbly. Press mixture into the bottom of a 10x15-inch jelly roll pan.
Beat cream cheese in another bowl with an electric mixer until fluffy. Gradually beat in pumpkin puree, sweetened condensed milk, 2 eggs, 2 teaspoons pumpkin pie spice, and salt until smooth. Pour pumpkin mixture over cake mix crust and sprinkle with walnuts.
Bake in preheated oven until set, 30 to 35 minutes. Allow to cool to room temperature and refrigerate until chilled. Cut into bars.
All done! Now take a photo, rate it, and share your accomplishments!