I also got to experiment with a product called Pastry Pride, which is a non dairy whipped topping mostly used to frost cakes. I normally use heavy whipping cream for my "frosting" as it is easy to work with and low carb compared to a buttercream frosting. I was impressed, it tasted amazing and really held up compared to whipped cream.
I also remembered to use the trick told to me by a sweet old Jewish lady which was to never cook your cake at more than 300 degrees and it will help it stay flat, which works every single time!
1 box of Devils Food Cake Mix
4 Heath Bars Crushed, I used the back of a small heavy sauce pan
1 quart of Pastry Pride or Heavy Whipping Cream
1 tbl pure Vanilla Extract
Make your cake mix and evenly pour into two cake pans, shake them a bit to get the bubbles out and make them even
Bake at 300 degrees for approximately 30 minutes, checking for doneness often.
Remove from oven when a tooth pick comes out clean, let cool
Whip your Pastry Pride or Whipped topping (be sure and add the Vanilla) until medium to stiff peaks form
Frosting the top, add in 1/2 your crushed Heath Bars
Add the 2nd layer, then frost the entire cake
You can use a piping bag and decorate as I did
Add the remaining 2 crushed heath bars on top