
Preheat oven to 350°F. Prepare a 9x13 dish by spraying with nonstick spray.
Make the cake according to the package directions for a 9x13 cake.
When the cake is done baking use the round handle end of a wooden spoon and poke holes all throughout the cake.
Pour the sweetened condensed milk all over the top of the cake and spread it out.
Then pour the caramel sauce over the top of the cake and spread it out.
Refrigerate the cake for at least two hours.
Spread the Cool Whip on top of the cooled cake and sprinkle with chopped Heath bars.