THE DAY BEFORE YOU NEED IT...bake cake in 9 x 13' cake pan according to directions. Make both puddings (in seperate bowls) & refrigerate.
Assembling trifle. Cut cake in 1/2. Then cut 1st 1/2 into bite sized chunks & place into trifle bowl. Take one pudding & spoon it over cake. Take one cool whip & spoon it over pudding. Take one package of heath bits (or 4 chopped heath bars) & sprinkle over cool whip. Drizzle caramel over. Repeat layers one more time.