Spoon cereal mixture into pan. Spray hands with cooking spray, and press mixture firmly in pan. Cover with waxed paper; press second 13x9-inch pan on top to compress bars. Remove pan and paper. Cool completely, about 1 hour. Remove bars from pan; peel off foil. Using sharp knife, cut bars into 8 rows by 6 rows to make 48 squares. Line cookie sheet with waxed paper.