Chocolate

Easiest Chocolate Mousse Cake

December 21, 2021
4.3
20 Ratings
Photo by Julia Gartland. Prop Stylist: Anne Eastman. Food Stylist: Lauren Lapenna.
  • Prep time 2 hours 50 minutes
  • Cook time 40 minutes
  • Serves 8 to 10
Author Notes

A dessert with several layers sounds complicated and time-consuming and therefore, no thank you. But here’s the deal: This one is none of those things. I remember enjoying chocolate mousse cake only at the end of special-occasion restaurant dinners with my parents in the ’80s (and yes, a puddle of raspberry coulis accompanied the slice). Teenage-me considered it the height of sophistication. And though it has since been replaced on dessert menus by trendier items, homemade chocolate mousse cake is timeless—a total showstopper—and, in this case, easy-peasy, too.

Here’s how: The base is a chewy cocoa brownie, inspired by Alice Medrich, studded with hazelnuts for crunch. It takes minutes to assemble (and if you’ve never had a brownie made with only cocoa, wowza are you in for a treat). The airy mousse doesn’t need gelatin or whipped egg whites. Instead, it’s made from whipped cream and melted chocolate mixed with water. Writing about Hervé This’ just-chocolate-and-water chocolate mousse, Kristen Miglore explains: “As you whisk, microscopic bits of water get suspended in the fat, thickening it and making it seem creamier. Then still more air is whipped into it and the cooling chocolate crystallizes around the air bubbles to make a remarkably stable foam, aka mousse.”

As a nostalgic nod to the pooled coulis of my youth, raspberries are folded in. Let it be said that while I am not a fruit-and-chocolate person, the berries here are nothing short of fantastic, adding unexpected juiciness to every bite. And the final layer is simply vanilla-smooched whipped cream, a wonderful, dare I say perfect, contrast to all the chocolate.

Once assembled, the cake needs at least a couple hours to set up, so plan accordingly. If you’d like, you can even make the brownie one day, then the mousse and cream the next.

Helpful tools for this recipe:
- Rosti Pebble Margrethe Nested Mixing Bowl Set
- Nordic Ware Springform Pan
- Mosser Glass Cake StandJessie Sheehan

Ingredients
  • Brownie
  • Nonstick spray or softened butter, for greasing
  • 3/4 cup (63 grams) Dutch-processed cocoa powder
  • 6 tablespoons (45 grams) all-purpose flour
  • 1/2 teaspoon Diamond Crystal kosher salt
  • 1/3 cup (47 grams) hazelnuts, toasted, skinned, and coarsely chopped
  • 1 1/3 cups (284 grams) light brown sugar
  • 1/2 cup (113 grams) unsalted butter, melted
  • 1 1/2 teaspoons vanilla extract
  • 2 large eggs
  • Chocolate Mousse
  • 1/3 cup (76 grams) hot tap water
  • 3 tablespoons Dutch-processed cocoa powder
  • 8 ounces (227 grams) semisweet chocolate, chopped
  • 1 3/4 cups (397 grams) heavy cream
  • 1/4 teaspoon Diamond Crystal kosher salt
  • 1 teaspoon vanilla extract
  • 1 1/2 cups (180 grams) raspberries
  • Whipped Cream
  • 1 1/2 cups (341 grams) heavy cream
  • 1 1/2 teaspoons vanilla extract
  • 2 tablespoons confectioners’ sugar
  • Raspberries, for serving (optional)
  • Dutch-processed cocoa powder, for dusting (optional)
In This Recipe
Directions
  1. Make the brownie layer: Heat the oven to 325°F. Grease the bottom and sides of a 9-inch springform pan (at least 3 inches in height) with nonstick spray or softened butter. Line the bottom with a round of parchment paper and the sides with a long strip.
  2. In a small bowl, whisk the cocoa, flour, and salt. Whisk in the nuts.
  3. In a large bowl, vigorously whisk the brown sugar, melted butter, and vanilla. Whisk in the eggs. Fold in the dry ingredients with a flexible spatula, just until the last streak of flour disappears.
  4. Transfer the batter to the prepared pan and bake for about 35 minutes, rotating the pan at the halfway point. It’s ready when a cake tester comes out with a few moist, almost wet, crumbs that can be rolled into a ball between your fingers.
  5. Turn off the oven and let the brownie cool on a rack on the counter (or in the refrigerator, if you’re feeling impatient) until it’s room temperature. (At this point, you can also wrap the brownie and wait for up to 24 hours to proceed to the next step.)
  6. When the brownie is room temperature, make the mousse: Whisk the hot tap water and cocoa in a small bowl. In a large heatproof bowl set over a pot of simmering water, melt the chocolate (or use a microwave if you prefer).
  7. In the bowl of a stand mixer fitted with the whisk attachment, beat the cream, salt, and vanilla on medium-high speed until the cream thickens but does not hold peaks. When you lift the whisk, the cream should form ribbons as it falls and hits the surface.
  8. Stir the cocoa mixture into the chocolate with a flexible spatula. Gently fold in the cream until just a few streaks of cream remain (no need to clean this bowl—we’re using it again soon). Gently fold in the raspberries. Scrape the mousse into the pan and evenly spread it over the cooled brownie. Transfer to the refrigerator.
  9. Make the whipped cream: In the stand mixer bowl fitted with the whisk attachment, whisk the cream, vanilla, and sugar on medium-high speed until stiff peaks form. Spread the cream over the mousse layer and refrigerate for at least 2 hours and up to 24. If refrigerating overnight, very lightly cover the cake in plastic wrap.
  10. When ready to serve, remove the sides of the pan and peel away the parchment. Slide a long, thin knife between the bottom of the pan and the parchment covering the brownie bottom and release the cake, placing the cake on a serving plate, and carefully peeling away the paper as you do so.
  11. For the cleanest slices, dip a knife in warm water before cutting. Serve with more raspberries and cocoa if you’d like. The cake will keep lightly wrapped in the refrigerator for up to 3 days.

See what other Food52ers are saying.

  • Jessie Sheehan
    Jessie Sheehan
  • sara.m.davis1032
    sara.m.davis1032
  • Richard928
    Richard928
  • Victoria
    Victoria
Bio: Jessie Sheehan is the author of The Vintage Baker and Icebox Cakes. Her new easy-peasy baking book, Snackable Bakes, hits shelves in spring 2022. She contributes to the Washington Post, Bon Appétit, Food Network, and the Kitchn, among others.

29 Reviews

sara.m.davis1032 October 2, 2022
Took this to a party and everyone thought it was restaurant-worthy. I was surprised that the mousse didn’t call for any kind of egg or cream of tartar but it worked. I would agree with other reviews that said the brownie base was dense, but my friends loved it. I would like to try it again with a base that is truly more like a brownie than fudge.
 
Jessie S. October 2, 2022
glad you liked!!
 
Richard928 April 11, 2022
I made this cake this last weekend. It turned out to be absolutely delicious. I let it sit in the refrigerator for 24 hours and it set up perfectly. Easy to make and definitely a keeper.
 
Jessie S. April 12, 2022
yahoo!! so happy to hear.
 
Victoria April 8, 2022
Truly an outstanding desert recipe. I make the brownie base the night before, then add the mousse and whipped cream topping the next day. Light, airy, cooling, and crunchy. The hazelnuts are a must and who doesn't love raspberries and chocolate!
 
Jessie S. April 8, 2022
thank you Victoria! i mean who doesn't love a glowing review??!! and so pleased you enjoyed. XO
 
Line H. March 19, 2022
Do not let the negative reviews fool you this is one of the best cakes I’ve ever made. Everyone absolutely loved it and said it belonged at a fancy restaurant. I do think it was easy in the sense that none of the steps required fancy and complicated techniques. I think there is still room for things to go wrong but that is not the fault of the recipe. That feels a bit like when people give a negative rating of an item because it wasn’t delivered in time for them… how is that a helpful review as to the quality of the item? This cake is amazing and I found the recipe easy to follow and well described. The brownie is just that. A fudgy intense brownie. If you don’t like that then maybe this cake just isn’t for you. We found it perfect.
 
Jessie S. March 20, 2022
Thank you so much for this review! You really get this cake and I so appreciate that!!!!! Also I am of course so pleased you liked it.
 
cyd February 23, 2022
I made this for our Valentine's dinner. The layers all came together and set properly. As someone else mentioned, the brownie was dense and chewy, but not in a bad way, imo. (My mousse wasn't overly "chocolate-y", but I also can't promise I didn't misread/mismeasure either the chocolate or cocoa.) According to my 8-year-old, dusting the top with the cocoa powder made it look "very sophisticated" - a descriptor not typically applied to my cooking, so I was quite flattered. Everyone loved it, and there were lots of leftovers to enjoy in the days following. I will definitely make this again!
 
Jessie S. February 23, 2022
so happy to hear that the cake passed the 8-year old's "sophisticated" test and so glad you will consider making again . . .
 
Debbylein February 17, 2022
I made this for a special Valentine’s Day dessert for our favorite neighbors - my husband especially is a chocoholic! Unfortunately, this was a fail, and I’m an easy grader on desserts. Followed the recipe exactly, and each layer came out perfectly; however, here is where it didn’t work out for me: the brownie layer was too dense and chewy; the mousse layer really needed a sweetener, and I used a high quality chocolate that should have made it palatable, but it just wasn’t - especially with the tart raspberries. Chocolate and hazelnuts = yum! Chocolate and raspberries = yum! But all 3 flavors in this recipe?? Nope, it just didn’t work.

I’d do this again, but sorry, I’d completely swap in a different brownie recipe and a better mousse recipe, then skip the raspberries (or just put one berry on top of each slice).
 
Jessie S. February 18, 2022
Sorry you didn’t like the flavors and good luck with your new version!
 
Niarae88 February 14, 2022
Followed this recipe exactly and it came out PERFECT! Such a treat and not overly sweet. I would probably even use a darker % chocolate for the mousse next time!
 
Jessie S. February 15, 2022
Yay!! LOVE hearing you made it as written and that it worked like a dream! Woo hoo!
 
Marie B. February 14, 2022
Made this today for Valentine’s Day. After reading the reviews, I decided to forge ahead with a few changes. I made the brownie and let it cool for 20 minutes while I made the mousse. After finishing the mousse, I put the brownie in the freezer and the mousse in an ice bath to cool it down quickly. Then I whipped the cream, took the brownie out of the freezer, layered raspberries on the brownie instead of mixing them into the mousse, per another review suggestion. Then I layered the mousse followed by the whipped cream and into the frig. I let it set for about 7 hours. It came out perfectly. The only thing I would do differently is when I take the brownie out of the freezer I would take the parchment off the bottom, put the brownie back into the springform pan and continue with the layering. I would still leave the parchment on the sides until final unmolding. It was delicious!! I would definitely make this again!
 
Jessie S. February 14, 2022
yay! so glad you liked and so many good suggestions!!
 
Cate February 13, 2022
Made this for valentine’s, it was delicious. My mousse layer set perfectly but the cream layer was not as set as I would have liked. In future I’ll make the bottom two layers and serve cream on the side
 
Jessie S. February 13, 2022
So glad it was yummy! And to insure your whipped cream is properly set you can over beat it a bit, till the peaks are really stiff . . .
 
Tsalstrom February 13, 2022
Made this exactly as stated in recipe except put a thin layer of raspberry jam in the top of the brownie to hold the raspberries in a standing position, then placed the mouse without extra raspberries on top and around each berry. Topped with whipped cream. Did cool it over night. It set perfectly. Everyone loved it. But don’t let the “easy” in the title fool you. It is an all day process, again totally worth it. Loved that it was not overly, sickly sweet. Just right!
 
Jessie S. February 13, 2022
Yay! Glad u liked. The “easy”
Is because you do not have to make a mousse with whipped egg whites, etc. There are def a lot of stores, but none of them is hard - or at least that was my intention!
 
Heatherstledger February 6, 2022
I was nervous to try this after reading the review of it not setting, I've had issues with cream pies not setting in the past but the recipe looked good so i decided to take my chance and made it for my birthday dinner. It was easy to make. I made the brownie the night before and the mousse and cream in the morning and let it set in the fridge for about 8hrs. I added 1 oz. Of chocolate since I was worried it might not set, I also whipped slightly past ribbon stage. All three layers turned out very good. The brownie is very rich, I also substituted mini chocolate chips for the nuts. The mousse and whipped cream balance the brownie very well. Everyone was impressed and thought this must have taken me much longer to prepare than it did.
 
Jessie S. February 7, 2022
glad you gave it a try and glad it worked out for you!
 
Kestrel February 5, 2022
I was intrigued enough by both the recipe and the negative comment chain that I decided to test out the mousse first, and the results were so delicious I plan on making the full 3-layers once I grab some unsalted butter, hazelnuts and raspberries! The mousse part of this recipe worked perfectly for me and was a big hit with my family.

I did a few things differently from the written recipe, since I was making just the mousse (no raspberries or brownie layer). First, I hand-whipped the heavy cream mixture in a medium sized mixing bowl (rather than lug out my KitchenAid) until it appeared thickened and at the classic ribbon stage. It took me about 2:45-3 minutes of continuous whisking to get to that point, and from past experience with hand-whipping it would have taken another 30 to 45 seconds to reach the soft-peak stage. The cream mixture was thick but still almost soupy and not quite where I’d want my mousse to be yet...but having read Hervé This’ Genius Recipe, I knew the chocolate would stabilize things, at least in theory.

I melted semi-sweet chocolate chips in a small mixing bowl in the microwave while I ran hot tap water. Once the chips were melted, I quickly whisked the coco and water together and dumped them in the bowl with the chocolate. A few whisks and I had a smooth chocolate sauce that was warm but not hot. I carefully drizzled this sauce over the cream mixture while folding it in, until the last streak of chocolate disappeared. I smoothed the mousse in the bowl and stuck it in the fridge. The texture of the mouse at this point was still ribbon stage. While cleaning up, I can confirm the flavor of the soft mouse was delicious!

I set a timer for 2 hours and checked the bowl every half-hour. After the first 30 my mousse was already beautifully set, and well before the two hour bell rung had no problem holding its shape. The flavor and texture were perfect, and there’s no question it would have worked beautifully in a layer dessert as well.

Now, obviously, mousse sandwiched between brownie and whipped cream might need the full 2 hours or even longer to set, but the mousse recipe above worked like a charm for me and was easy to make, even though I was a bit skeptical the cream/chocolate would stabilize into such a perfect foam. I’ll post back in a few days once I make the full 3-layered version, ‘cause I think my family is going to make short work of this delicious mousse!

When I do make the full recipe, though, I plan to cool and chill the brownie layer before making the mousse, since even a slightly warm brownie could mess with the texture of the cooling chocolate/cream. I’ll also probably use frozen rather than fresh berries and just lay them on top of the brownie and cover with the mousse…no real need to stir the berries in since they’ll probably fall towards the bottom of the layer anyway.
 
Jessie S. February 5, 2022
I’m so happy to hear all this! And I look forward to hearing how the mousse works when you make the cake. The raspberries don’t actually sink, so if you’d like to fold them in to the mousse, I’d encourage you to do so! Thanks again for your thoughtful comment.
 
Becky M. January 22, 2022
Just as I suspected, the Mousse wasn't firm enough to hold after 2 hours of refrigeration. I am so upset I was counting on this for a special occasion and everything else was prepared perfectly. I even submitted a question with no response. BEWARE it DOESN'T HOLD add a thickener to mousse or it will FAIL. Also learned my lesson to NEVER make a recipe with NO REVIEWS.
 
Jessie S. January 22, 2022
Wow. So sorry your mousse did not hold. This recipe has been carefully tested several times before being published and has been made by several Food52 community members as well, so I am not sure what went wrong when you made it, but again - I am so sorry.
 
Becky M. January 22, 2022
I’m just tired because now I have to make another cake unless the 2 hours was too soon to unmold, but I wont know until it’s too late. I followed the recipe exactly. Maybe whip cream should be stiffer. What’s the point of it just to ribbon stage?
 
Jessie S. January 22, 2022
I understand. If you have the time perhaps let it set for longer than 2 hours? Did you take it from the fridge at exactly 2 hours? And was it visibly jiggly and not set? Or you could not tell till you sliced it? Also, when you over whip it the texture is not as light and fluffy and airy. The ribbon stage gives it just enough structure without negatively impacting the texture. Also, as I said in the headnote, “As you whisk, microscopic bits of water get suspended in the fat, thickening it and making it seem creamier. Then still more air is whipped into it and the cooling chocolate crystallizes around the air bubbles to make a remarkably stable foam, aka mousse.” - this is the “scientific” reason for how the mousse stabilizes - the water mixed with the fat of the cocoa powder and cream . . .
 
Becky M. January 22, 2022
Yes I had my timer set for 2 hours and was going to remove the side parchment and top with the whipped cream. The sides of it were loose not the center part so when I removed the springform it started to weep out, I put the spring form back on and stuck it back in the frig hoping and praying it will firm up.