Prehat oven to 350 degrees F
Line a 13x9-inch baking dish with aluminum foil and spray foil with non-stick spray.
In a large bowl, combine the cake mix, egg and melted butter; blend well
Press cake mix dough into the prepared pan, forming an even crust; set aside.
Combine pumpkin, cream cheese, brown sugar, dry pudding mix and eggs in another large bowl.
Beat until smooth and pour over the crust already in the pan.
Bake at 350 degrees F for 35-40 minutes or until center is almost set.
Remove from oven and cool in pan for 10 minutes.
Using the aluminum foil as handles, remove the bars from the baking pan and set on a rack to cool completely.
Prepare topping by adding the envelope of Dream Whip the milk and maple syrup to a bowl.
Mix on low speed of mixer until blended then beat at high speed for about 4 minutes, or until stiff peaks form. The topping may be refrigerated until ready to use.
Spread Dream Whip mixture on top of cooled bars. Garnish with ground cinnamon.
Refrigerate any leftovers.