What is Crème Mousseline?

Those of you who have a hang-up about dietary fat, plug your ears. Classic crème mousseline is a 2-1 (by volume) mixture of pastry cream and cool butter, whipped together into a rich, silky foam. It could only have been invented by the French, God love those people. If you want you can substitute stabilized whipped cream in your fraisier, but really…do you want to miss this? No, I thought not.

18 thoughts on “What is Crème Mousseline?”

  1. I have never run across this before. I’m not sure if I would like it or if it would be a bit too much. The first time I made a French recipe for Chocolate mousse I added the butter it called for & found the end results to have that unpleasant waxy mouth feel and was very heavy. I would make it with half or less of the butter if I ever did that again. But I just make a version without the butter now.

    1. Hey Frankly!

      There are so many chocolate mousse recipes out there…I probably wouldn’t favor butter in mine, however I do like chocolate buttercreams. It’s all in your expectations I think. Something that seems perfectly appropriate in one context is odd in another…as much as I try to never say no to butter.

      – Joe

  2. It seems that every patissier has his own understanding of what the various creams are. I recently made mousseline according to Bouchon Bakery and it was the most fabulous tasting creation. It involves a 1:1 mixture of thick pastry cream and basic buttercream. The latter, according to Bouchon, is an Italian meringue based buttercream.

    1. Hi Ariel!

      That definitely counts as mousseline cream. I use that combo to fill my tart Tropézienne. And you’re very right that different pastry makers have different interpretations of various creams. I think in this case it’s just a different road to the same place, since the proportion of butter to pastry cream ends up being the same. The extra eggs foam certainly makes it a little lighter in texture though. Thanks for the great comment!

      – Joe

  3. Our customers find that mousseline is a little too heavy for their tastes. We sub a straight strawberry mousse.


  4. Hi Joe

    How exactly does the butter and pastry cream get whipped together into a foam? Is there a special technique? It just seems to me – playing it out as a thought experiment – that the butter would make the pastry cream heavier.

    1. Hey Gretchen! I probably led you astray there. They do create a foam from all the whipping, but a very tight one…not nearly as fluffy as whipped cream…but generally lighter than whipped butter.

      Thanks for helping me clarify,

      – Joe

  5. hi Joe Pastry,
    I’m about to make a crème mousseline and was going to use Michel Roux’s recipe which says to make a pastry cream with 4 eggs and 2 yolks. Can I use my regular recipe which uses 6 yolks, no whites? Do the whites make a difference for whipping in the butter?
    thanks for your advice

    1. Hi Elaine!

      You can indeed use the recipe with the six yolks. The butter is what gives mousseline its texture.

      Have fun!

      – Joe

  6. Hi Joe Pastry,
    I know your post is a little old now but just wondering if crème mousseline is a shelf stable product or how long it can be left at room temp when made with Italian Meringue buttercream. I have seen it used as a filling for celebration cakes which are then masked in a layer of ganache then rolled fondant. Would love to try it but I’m concerned about it being at room temp for 2 days whilst cake is being assembled & decorated. Thoughts?

    1. Hey Brigid!

      Wow does that ever sound good. It’s not the buttercream I’d worry about as much as the pastry cream, which is of course a custard and needs to be refrigerated. Two days would be entirely too much to my mind. Can you send me a picture of this wondrous creation though? I wonder if there’s way to do it make it food safe. Pasteurized eggs would be a start!

      – Joe

  7. Could you use mousseline to mask a cake, or is it too soft? I love the flavour and texture of mousseline over italian buttercream!

    1. Interesting idea, Shannon. It is very soft. You could cover a cake with it, but it would be like painting a cake with custard. I’d be more inclined to use it as a filling. And perhaps there’s an idea in that: between layers, a scraping of IMBC with mousseline over it. Then little or nothing on the exterior. Call me crazy.

      Send a photo of your experiments!


      – Joe

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