(Almost) everything you could want to know about chocolate cake fillings, all in one place! This post contains affiliate links. For more information, see my disclosure policy.

s small chocolate cake on a glass pedestal on a dark background. Text reads chocolate cake fillings: recipes and techniques

Hi all. Elise asks,

What is the difference between chocolate truffle, ganache, and chocolate mousse cake fillings? How do I know which to choose for my cake?

This is a great question, partly because it’s a question, and I love answering questions, but also partly because it illustrates an issue of semantics. And here we go.

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Chocolate Cake Fillings

Ganache, truffle, mousse.

Technically, these two chocolate cake fillings, ganache and truffle, are the same thing.

They look like the little fungus truffles, hence the name.

So, there is really no difference at all between ganache and truffle filling.

Having said that, nothing is ever as simple as that. There are different ratios of chocolate to cream to make different consistencies of ganache.

Versatile Ganache as a Filling or Frosting

Ganache made for truffle fillings is, more or less, 2 parts chocolate to 1 part liquid (predominantly cream but also could include a flavored liquid such as wine or coffee or a liqueur).

Ganache made with equal parts chocolate and cream (1:1) will not set up as firmly as a classic truffle filling and is best used as a cake glaze.

Make a ganache with 1:2 chocolate to cream, chill it, and then you can whip it. This gives you a more-or-less instant chocolate mousse that you can use as a filling and/or a frosting. You can even use a 1:1 ganache “straight up” for filling and then whip it for frosting. Or vice versa. It’s very versatile.

See my recipe for Chocolate Cake with Whipped Ganache Frosting for the low-down.

Ever have your ganache get grainy and weird? It has probably broken, meaning it is no longer a lovely emulsion of water and fat. Learn how to fix your broken ganache without changing its texture.

It didn’t take long for the third term to crop up, did it? Mousse.

Mousse for Cake Fillings

Mousse means “foam” in French, so pretty much anything foamy or lightened with whipped egg whites (very foamy stuff) is a mousse.

What I think of when someone says “chocolate mousse” is the basic French kind: melted chocolate (and maybe some butter), egg yolks whisked in followed by whipped egg whites (hello foam) and whipped cream (hello, more foam).

Hey, wait. Chocolate + cream = ganache or truffle filling. And it also equals mousse when you whip the cream first. Magic!

Here’s an excellent mousse filling in this classic Chocolate Mousse Cake recipe.

Classic mousse does differ in one way from truffles/ganache in that the majority of chocolate mousse recipes contain eggs. This allows them to be smoother (emulsifiers) and billowy (whipped egg whites) as well as containing more protein.

So, in more complete answer to the first part of Elise’s question, there is very little difference in ingredients among truffle, ganache and mousse fillings. There may be a marked difference in texture, certainly with the mousse, but also if you whip the ganache.

If you need a primer on making ganache, I just happen to have a video for you.

Cookbooks for Cake Fillings and Frostings

Part two of Elise’s question is how to choose which filling for which cake.

Honestly, I think you should just choose what you like. Make a ganache and call it ganache or a truffle filling. Or whip it and call it mousse. Or make a dense mousse and call it truffle filling.

I think the main thing to consider is that cakes with dairy in the filling/frosting should really be refrigerated for safety’s sake.

To Refrigerate or Not Refrigerate Your Cake and Cake Fillings

Knowing that bit of information, if you’re planning on filling/frosting/glazing your cake with chocolate ganache, truffle filling or mousse, stick with cake recipes that don’t get hard in the refrigerator, that is, ones that don’t contain fat that is super hard at refrigerator temperatures (butter, coconut oil).

Choose cakes that use oil as the fat (chiffon or old fashioned red velvet and similar) or ones that don’t contain any fat, or just minimal fat (genoise, sponge cake, angel food cake).

That way the fat (along with the rest of the cake) will have a chance to come up to room temperature and soften. Butter cake straight out of the fridge reads as dry because the fat in them gets so hard. Give it time to settle down and warm up, and then it’ll be nice and moist for you.

Even cakes that don’t contain butter will taste better if given a chance to sit out at room temperature for 30 minutes or so. The frostings and fillings will have a chance to temper a bit and have a softer, dreamier texture. If you’re going for a “fudgy” texture, though, by all means serve cold.

How to Pair Cakes with Fillings

One more thing to consider when pairing a filling/frosting and a cake is texture.

  • You may want to pair a light and airy mousse filling or whipped with a dense, rich cake (perhaps a flourless chocolate cake).
  • Pair lighter, airy cakes (genoise, angel food, sponge) with a thicker ganache/truffle filling.

It’s all about balance, Not that there aren’t times when you want fudgy cake slathered in fudgy frosting, because of course you do. Sometimes that’s necessary.

Generally speaking, it’s nice to offer some textural contrast on a plate, and pairing a light cake with a dense filling (or vice versa) is a simple way to accomplish that goal.

My Favorite Flavor Pairing for Chocolate Cake

My favorite chocolate cake is chocolate stout cake. And the perfect filling for it is burnt caramel buttercream.

I implore you to make both. You will love them!

Add A Little Crunch to Your Cake Fillings

While pairing dense with light is always a good rule of thumb, adding some crunch really keeps your mouth interested. You can add crunch by folding in bits of candy or cookies, toasted nuts, feuilletine, etc.

And there you have it. I hope you this little primer helpful. Thanks so much for the question, Elise.

More Chocolate Cake Fillings from Around the Hinternets

If any of you have a question you’d like me to answer here on the blog, just shoot me an email and I’ll help!

PS There is no rule that says you can’t frost a cake with mousse and then drizzle it with ganache. Just in case you were wondering.

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  1. Hi! I would love your expertise help! My niece is getting married and wants a butterscotch cake. I have done 3 different recipes I found online , but I have had no luck in finding the perfect cake mix. One came out too dense, the other too dry, and last too heavy. She says it’s spongy like three milk cake version. It had praline crunch. I got the praline down , but the cake part not so much. I would appreciate any help. Thank you in advanced.

    1. I have a Butterscotch Cake recipe on the blog you may want to take a look at. https://pastrychefonline.com/butterscotch-cake/ The cake part is a nice, rich butter cake. If you want more of a sponge cake, you can get the butterscotch flavor by subbing dark brown sugar for white and using browned butter rather than regular butter in your favorite sponge cake recipe. The praline sounds dreamy. Butterscotch is my favorite! Hope this helps.

  2. Hi I was planning on making a Duncan Hines french vanilla 8 inch layer cake which I was going to frost with white chocolate gnache and I wanted to use a semi sweet choolate mousse filling how much cream should I use for the filling any help would be appreciated.


    1. Hi Jane. Sorry for the delay in getting back to you. I like your plan! The cake sounds great! One question I have is how many layers are you making? Are you cutting each of your 2 layers in half, or are you just using the 2 layers or maybe baking the cake in 3 pans? That will certainly have an impact on how much filling you make since for 2 layers, you’ll only need 1 amount of filling, for 3, you’ll need 2 and for 4 layers you’ll need 3. (I hope that makes sense). I’d also imagine that the more layers you’ll have, the less filling you’ll need per layer. I would say you would need 1/2 cup filling if you’re doing a 2-layer cake, 2/3 cup if you have 3 layers and maybe 3/4-1 cup if you’re making 4 layers. Hope that helps!

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