Preheat oven to 350 degrees F. Spray a 6.5 inch cast iron skillet with cooking spray and set aside.
In a small bowl, stir together cookie mix, pumpkin, and egg whites. Pour batter into the prepared skillet and spread until evenly distributed. Sprinkle with crushed cereal.
Bake for 30 minutes. Remove from oven and let cool completely before slicing into 8 pieces.