Preheat oven to 350 degrees Fahrenheit. Grease a 9"x13" cake pan. For the cake base, in the bowl of an electric mixer, mix together cake mix, egg, melted butter and milk until incorporated. Batter will be thick. Smear butter on your hands and press mixture into the bottom of prepare pan. You'll need to keep rubbing more butter on your hands as you go so the mixture doesn't stick to them. Bake for approximately 15 minutes.

While it's cooling, prepare cheesecake topping by mixing together cream cheese, powdered sugar, vanilla and pumpkin pie spice until mixture is smooth and creamy. Add in pumpkin puree and mix on a high speed until creamy. Fold in whipped topping. Spread over cake crust and sprinkle with pecans. Store, covered, in the refrigerator until ready to serve.