Preheat oven to 350 F. and spray a 7x11 pan with pan coating. Sift together flour, cocoa, sugar, baking soda, cornstarch and salt. Beat applesauce, vanilla, corn syrup, sugar, and water with a mixer until well blended. Mix dry mixture into wet mixture until very smooth. Fold in chocolate chips and (optional) walnuts. Bake 24 minutes.