Preheat oven to 325 and grease a 9x13 pan with cooking spray.
Mix cake mix, butter and 1 egg in a bowl by hand. The dough will take a bit to come together but it will. Evenly press into prepared pan with your fingers. Set aside.
In the same bowl, beat cream cheese for about 1 minute. Add 2 eggs and beat well. Add pumpkin puree and pumpkin pie spice and beat well. Add powdered sugar, 1 cup at a time and beat after each addition.
Pour into prepared pan, over cake and spread evenly.
Bake 40-45 minutes. Cool completely. Top with walnuts and caramel before serving.