Heat oven to 350 (325 for dark or nonstick pan) Grease or spray bottom only of 13x9 inch pan
In large bowel,beat cake mix,water,butter & eggs with electric mixer on low speed 30 seconds,thenon medium speed for 2 minutes. Pour into pan
Bake 31 to 36 minutesor until toothpick comes out clean. Cool 15 minutes.Poke to of warm cake every 1/2 inch with handle of wooden spoon, wiping handle occasionally to reduce sticking. Reserve 1/2 cup carmel topping. Drizzle remaining carmel toppng evenly over top of cake;let stand about 15 minutes or until carmel topping has been absorbed into cake. Run knife around side of pan to loosen cake. Cover and refrigerate about 2 hrs or until chilled.
Set aside 2 tablespoons of the reserved 1/2 cup carmel topping. Stir remaining topping into frosting;spread over top of cake. Drizzle remaining carmel topping. store covered in refrigerator.