Chocolate Mousse Crunch Cake

This Chocolate Mousse Crunch Cake is my all-time favorite special occasion cake. Not only does it wow people presentation-wise, but it’s pretty knock-your-socks-off tasty as well. As long as you like chocolate. Because if you’re a chocolate hater, this recipe isn’t for you.  It’s got 2 layers of rich chocolate cake, sandwiched with decadent chocolate mousse, drizzled with ganache and sprinkled with chopped toffee bits.  If you like, you can even top it with a cloud of whipped cream like I did in these photos.

chocolate cake on cake stand

Make-Ahead Options

One of the great things about this easy chocolate cake recipe is that you can just use a boxed cake mix. I figure that there’s so much going on here that you don’t need to bother with a from-scratch chocolate cake, you know? And if you make the ganache ahead of time and just heat it up, and make the cake ahead of time, by a few hours or a day or even a few days (just wrap the layers in plastic wrap and freeze them), the rest comes together in no time.

chocolate cake on platter

You can bake the cake layers ahead of time if you like and store them in the freezer until ready to use.  Our favorite cake pans to use are the kind with straight sides like these ones. The filling for this cake is a rich chocolate mousse that’s incredibly easy to make.  It actually makes more mousse than you probably need, so feel free to fill it as thick or as thin as you like and snack on the rest- because you made the cake so you get the extra mousse!

cake with mousse filling

Fill and Top the Cake

This chocolate cake is topped with…you guessed it- more chocolate. To get nice drips down the sides, avoid trying to actually spoon ganache down the side of your cake.  Spread a nice even layer right on top.  Then use a spoon to gently start spreading toward the edges.  You just need to nudge a little and you’ll see the chocolate wave start moving toward the side and down the edge.  Let gravity do the work!  That way you get nice pretty drips without overdoing it.  You can sprinkle some toffee bits on top and you are ready to serve!

ganache dripping on cake

OR, if you like, I sometimes like to top it with a fluffy cloud of sweetened whipped cream as well.

chocolate cake with whipped cream on top

Helpful Tools for this Recipe

Straight-Sided 8″ Cake Pans

chocolate mousse cake on cake stand

Chocolate Mousse Crunch Cake

5 from 1 vote
An easy chocolate mousse and toffee filling is sandwiched between moist layers of chocolate cake and finished off with rich, gooey ganache and more toffee bits.


  • 1 package Duncan Hines Devil’s Food Cake
  • 1 recipe give or take a little Chocolate Ganache
  • Crushed Heath bars or a bag of chocolate-covered Heath bits
  • 1 teaspoon unflavored gelatin
  • 1 tablespoon cold water
  • 2 tablespoons boiling water just heat it in a small bowl in your microwave
  • 1/2 cup sugar
  • 1/4 cup unsweetened cocoa powder
  • 1 cup whipping cream
  • 1 teaspoon vanilla
  • Optional: extra sweetened whipped cream for serving


  • Bake cake according to cake mix instructions in 2 8″ round pans. Allow to cool and set aside. This can be done several days in advance; just freeze the cakes when you’re done.
  • In a small bowl, combine gelatin and cold water and allow to stand for about 1 minute. While gelatin is softening, bring about 1 cup of water to a boil in the microwave and measure out 2 tablespoons. Discard the rest. Whisk the 2 tablespoons of boiling water into the softened gelatin and allow to cool slightly.
  • In a medium mixing bowl, combine sugar, cocoa powder, whipping cream, and vanilla. Beat with an electric mixer until medium-stiff peaks form. Mix in gelatin mixture and refrigerate for 30 minutes.
  • Prepare ganache (if you haven’t already) according to directions.
  • With a serrated knife, carefully slice the dome-iest part of each cake layer off so the layers are level. Place one layer on the serving plate and spread chocolate mousse over the cake (see note below). Sprinkle with Heath bits.
  • Place second layer on top of Heath bits.
  • Spoon ganache over the top layer, allowing it to drip down the sides.  Sprinkle with additional Heath bits and refrigerate until ready to serve. If desired, top with sweetened whipped cream before serving.


This recipe makes more mousse than you will probably need. Feel free to use as much or as little as you desire in the filling and snack on the rest!
Keyword: Chocolate Cake, Chocolate Crunch Cake, Chocolate Mousse, Occasion cake
Author: Kate Jones
Did You Make This Recipe?Snap a picture, and hashtag it #ourbestbites. We love to see your creations on our Instagram @ourbestbites!
woman in denim shirt holding a salad bowl
Meet The Author

Sara Wells

Sara Wells co-founded Our Best Bites in 2008. She is the author of three Bestselling Cook Books, Best Bites: 150 Family Favorite RecipesSavoring the Seasons with Our Best Bites, and 400 Calories or Less from Our Best Bites. Sara’s work has been featured in many local and national news outlets and publications such as Parenting MagazineBetter Homes & GardensFine CookingThe Rachel Ray Show and the New York Times.

Read More

Join The Discussion

Your email address will not be published. Required fields are marked *

Recipe Rating

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Questions & Reviews

  1. Oh my word! I for one love chocolate, and can't get enough! I need to try this cake, like immediately. Yum!

  2. What a beauty. That treasure looks right up my alley. Thanks for sharing, gals!

  3. That looks so good! Congrats on your blog. If I could change one thing…it would be for you to add an option so I could print recipes on 3 x 5 or 4 x 6 card sizes. Otherwise, I wouldn't change a thing!

  4. Wow! This looks AMAZING!! I have missed your blog so much. [We had laptop issues for months and have now upgraded to a brand-new one – wahoo!!] I am half-tempted to go back through ALL of the posts I missed and catch up.
    Time to wipe the drool of the new computer…. 😉

  5. Looks delish, but like Amber I'm curious what do you do with the other half of the chocolate mousse? Or is it possible, dare I say, to make a half batch of the mousse?

  6. omg, I'm going to hate you for this…

    However, I will counter your triple chocolate monster with this Chocolate Stout Cake. Beer & chocolate, what could be better? (and the alcohol burns off – I serve this to kids)

  7. My job is dessert every Sunday when my extended family gets together. This looks wonderful and I will be making it this weekend! Thanks for all of your wonderful ideas.

  8. That looks SOOO good! Now I need to plan something so I'm not left with half a cake to myself at home all day long….you know? Thanks for the great recipes, looking forward to the next year of delicious food and great ideas!

  9. That is insane… OMG amazing and I am sure worth every calorie!! Looks incredible!

  10. Good thing I don't have a very good reason to make this anytime soon… this looks very dangerous!!(I am sure I will come up with a reason soon!)YUM!

  11. Looks divine!! I will have to make this soon. My husband will just love it! 😀 Thanks for the great posts, I look forward to reading them!

  12. This looks wonderful. I am preheating my oven right now so I can make it. Just thought I'd point out an easy way to avoid the problems you might have by halving the mousse recipe -just boil a quarter cup of water and then measure out the 1 tablespoon that's needed.

  13. Wow, that looks FANTASTIC! Thank you for the blog you inspire me to be more adventurous!

  14. Happy birthday. This was so not the post a pregnant chick should open first thing in the morning! Drool on the computer could totally be bad. My bday is coming up in April and I am trying to figure out who I could print this out for and con/beg/plead/strong arm into making this for me!

  15. Wonderful! Happpy Birthday! NOw, I just wish you could have sent everyone a piece? Wouldn't that be something?

  16. I think this just became my favorite cake too – chocolate, layered with chocolate & then topped with chocolate – YUM! Can't wait to try this :)Happy Birthday!

  17. Looks fan-freakin-tastic!!

    Am I just missing something or do you only use half the mouse? What do you usually do with the extra? Just eat it cuz that'd be great or do you make something else?

  18. This cake looks heavenly! I think rich is an understatement!!! My anniversary is next week and my hubby LOVEs mousse, so this will make for a perfect dessert! Thanks for sharing, I really enjoy your blog and the yummy recipes!

    1. I used this recipe to upscale my daughter’s request for a chocolate birthday cake. Everyone loved it! Thank you!