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(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.
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.
Chocolate Cake Fillings
Ganache, truffle, mousse.
Technically, these two chocolate cake fillings, ganache and truffle, are the same thing.Traditional, authentic truffles are nothing more than ganache rolled into little lopsided balls and dusted with cocoa powder.
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.
Fillings for Yule Logs and Jelly Rolls
Well, you can obviously use jelly–or jam, since it’s easier to spread.A classic jelly roll filling is a layer of jam and a layer of whipped cream. Nice!
Here are more recipes for wonderful filled jelly roll and Yule log cakes:
- Chocolate Yule Log with Cran-Razz Filling
- Classic Pumpkin Roll
- Ermine Frosting–The classic frosting for Red Velvet Cake, makes a gorgeous, smooth filling
- Pink Velvet Yule Log with White Chocolate Cream Cheese Filling
- Buche de Noel with Chocolate Buttercream OR Chocolate Mousse Filling
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).It's possible to make a simple chocolate mousse with just melted chocolate folded together with cream whipped to medium peaks.
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.
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
Apparently there used to be a time when cake was served without frosting. Let’s be glad we live now, when we can buy cookbooks full of cake fillings and frostings recipes!
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).If you simply must make a butter cake (because pound-cake-I-love-you-so-much), make sure it sits out for at least an hour or so before serving.
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 Cake 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.
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.
Here are some specific suggestions for you.
Pro Tip: No reason not to use these crunchy additions in ice cream recipes, too!
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
- Chocolate Cake with Chocolate Mousse Filling (contains coffee and Nutella in the mousse)
- Chocolate Truffle Cake (chocolate layers soaked in orange syrup, whipped ganache filling)
- Chocolate Cake with OREO Cheesecake Filling (what?!)
- Ding Dong Cake (Chocolate Cake with Ermine Filling)
- Chocolate Mayonnaise Cake with Rocky Road Frosting (Nuts and marshmallows textural contrast to this rich frosting)
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.