1Heat oven to 350°F. Spray bottom only of 13 x 9-inch pan with cooking spray. In large bowl, stir cookie mix, oil, water and egg until soft dough forms. Press dough in bottom of pan. Bake 12 to 15 minutes or until light golden brown. Cool completely, about 30 minutes.
2Spread hot fudge topping over cooled cookie base. In large bowl, combine frosting and peanut butter until well mixed. Add whipped topping and candy; gently fold until well blended. Spoon mixture over hot fudge topping then carefully spread to evenly cover. Refrigerate about 2 hours or until chilled. For bars, cut into 6 rows by 4 rows. Store covered in refrigerator.