HEAT oven to 350°F.
LINE 13x9-inch pan with foil, with ends of foil extending over sides; spray with cooking spray.
Mix cake mix, 1 egg and butter until blended; press onto bottom of prepared pan.
BEAT cream cheese, brown sugar, remaining eggs, pumpkin and dry pudding mix with mixer until blended; pour over crust.
BAKE 40 min. or until toothpick inserted in center comes out clean; cool 10 min. Use foil handles to transfer dessert to wire rack; cool completely.
MEANWHILE, mix whipped topping mix, milk and syrup in large bowl with mixer on low speed until blended. Beat on high speed 4 min. or until mixture forms stiff peaks. Refrigerate until ready to use.
SPREAD whipped topping mixture onto dessert and sprinkle with cinnamon before cutting into bars to serve.
OPTIONAL: Garnish with toasted pecan halves.