1. Coat a 13- x 9-inch pan with cooking spray. Combine pumpkin and next 5 ingredients in a large bowl; pour into pan. Sprinkle cake mix over pumpkin mixture, and top with pecans. Drizzle with melted shortening.
2. Bake at 350º for 40 to 45 minutes or until golden. Let cool 2 hours or until completely cool. Serve with sweetened whipped cream.