Bake the cake in 9" round cake pans. Follow the directions on the box, including cooling directions.

Once the cake is totally cooled, use a bread knife to slice the cake layer into two thin cake layers.

Place one of the thin layers in the bottom of your trifle dish.

Following the directions on the jar, heat up the hot fudge sauce.

Pour a thin layer of hot fudge over the cake layer, using the back of a spoon, work the fudge to the edge of the cake.

Allow the hot fudge to cool before moving on.

Add a thick layer of Cool Whip, spreading it all the way to the edges.

Pour a single layer of the Heath Bar Bits on top of the Cool Whip.

Repeat the layers again: thin layer of cake, hot fudge, Cool Whip, Heath Bar Bits.

If there is room in your trifle bowl repeat the layers again.

If not, take some of the remaining cake in your hands and crumble it over the top of the trifle until it is covered.

Then sprinkle on some of the remaining Heath Bar Bits.

Use a large spoon to serve the trifle.