Step 1

Prepare the cake according to the directions on the box for a 9x13-inch pan. Bake for 10 minutes and then sprinkle the surface with the chocolate chips. Continue baking until the cake tests done.

Step 2

Remove the cake from the oven and immediately poke holes all over the top using either the bottom of a wooden spoon, a skewer or a fork.

Step 3

Pour the sweetened condensed milk slowly over the top of the cake. Chill for 1 hour or until cool. Spread the caramel sauce over the cake.

Step 4

Spread the Cool Whip over the top of the caramel sauce, top with the crushed Heath bars, and refrigerate again for at least 1 hour. Serve cold and refrigerate any leftovers.