Chocolate Cake with Chocolate Mousse and Gianduja Buttercream + It's My Birthday!

So, in case it's not glaringly obvious from the photos and the title, IT'S MY BIRTHDAY!

I'm the big ol' 22 this year! That makes me a real live adult, right? I still feel like an immature little 16 year old that bugs everyone, though. I still talk to my cat. I eat toast for dinner more times than I'd like to admit. I still don't have my drivers licence. I don't really know what a mortgage is.

I'd love to tell you that I've got some sweet plans for tonight - it is a Friday after all. Instead, it's 6:30 am and I'm getting ready for a 10 to 12 hour work day. After that, I'm going straight home and right to bed because I'm doing the 5 am shift tomorrow morning and have to wake up at 3:30 am. Wooooh, crazy party fun times! Ha.

All joking aside, I don't mind working on my birthday. First off, I love my job. Secondly, I'm not much of a partier, never was. And thirdly, my excitement for Christmas is totally overshadowing my birthday. I've already made and shot a bunch of Christmas recipes and I just can't wait to decorate my apartment and hear Christmas music and see twinkling lights everywhere. I'll probably start putting up my lights and decorations on my next day off.

Also, I find that I'm coming to the point where my birthday isn't as big of a deal as it used to be. When I was a kid and I used to see an adult just shrug off their birthday, it was unbelievable. No party, no presents, no acknowledgement?! What??

But now, I'm kind of like that. I'd like some people to acknowledge that it is my birthday, but I don't really need any birthday presents and I certainly don't need a party. It's just another day. 
Man, it is really sad to write that out. I guess maybe that's when you know you're an adult? Or maybe I'm just boring.

Chocolate Cake
Recipe adapted from Elements of Dessert

20 g cocoa powder
220 g all-purpose flour
4 g baking soda
2 g salt
150 g unsalted butter, at room temperature
266 g icing sugar
66 g eggs
163 g buttermilk

Dark Chocolate Mousse
Recipe from Elements of Dessert

60 g eggs
25 g sugar
80 g good quality dark chocolate (70-73%), finely chopped
131 g heavy cream

Gianduja Buttercream

57 g egg whites
86 g sugar
170g unsalted butter, soft, cut into 1/4 inch dice
150 g gianduja

For the chocolate cake, sift the cocoa powder, flour, baking soda, and salt together. Set aside. Line a half sheet pan with parchment paper, then spray the borders of the sheet pan. Set aside.

Preheat the oven to 325 F.

Cream the butter and icing sugar together in an electric mixer fitted with the paddle attachment on medium speed until it is light and fluffy, about 4 minutes. Add the eggs in 2 additions, scraping the sides of the bowl and the paddle between each addition. 

Add half of the sifted dry ingredients and mix for a few seconds, until combined. Add half of the buttermilk and mix for a few seconds. Repeat with the other half of the dry ingredients and the remaining half of the buttermilk.

Pour the batter onto the prepared sheet and spread evenly with an offset spatula. 

Bake for 10 to 15 minutes. Remove from the oven and let cool to room temperature. Once it has cooled, lift the cake and parchment off of the sheet pan and flip it upside down. Carefully peel off the parchment. Line the sheet pan with a new sheet of parchment and gently place the cake on that. Freeze until hard, about 20 minutes.

Using a 7 inch cutter (or bowl/mug/etc. and using a small paring knife), cut out 4 rounds from the frozen cake. Discard the scraps of cake or use for other desserts. Reserve the cake rounds in the freezer.

For the chocolate mousse, place the eggs and sugar in the bowl of a stand mixer and place over a hot water bath while whisking constantly until it reaches 60 C/ 140 F.

Remove the mixture from the heat and place it in the stand mixer. Whip on high speed until it cools to about 35 C/ 95 F and creates ribbons, about 10 minutes.

Meanwhile, melt the chocolate over the hot water bath. Let it cool to 35 C/ 95 F.

Once both the egg mixture and the chocolate are at the correct temperatures, whisk the egg into the chocolate until evenly combined. Fold half of the whipped cream into the chocolate mixture, then fold in the remaining half. 

Place one round of cake on your turntable. Gently spread about 100 g of mousse onto the first round, gently spreading the mousse almost to the edges with a small offset spatula. Repeat the process with the remaining rounds, but do not put mousse on top of the fourth cake round.

Place in the fridge until set, about 2 hours.

For the buttercream, melt the gianduja over a double boiler until melted. Set aside.

Whisk together the egg whites and sugar in the bowl of a stand mixer and place over a double boiler. Whisking constantly, warm the egg whites until the mixture is no longer gritty. Immediately transfer to the stand mixer and whip on medium-high for 4 minutes, until glossy and no longer warm. 

Slowly add the butter, piece by piece, until the buttercream forms. The buttercream may look like it has split initially, but if you continue to whip, it should form a smooth, fluffy buttercream. 

With the mixer on lower speed, slowly pour in the melted gianduja, stopping to scrape down the sides and bottom of the bowl. 

Take the cake out of the fridge. Apply a crumb coat of buttercream to the cake, then refrigerate for 20 minutes. Apply the rest of the buttercream to the cake and smooth the corners, sides, and top. 

For the look that I created, I refrigerated the cake for another 20 minutes after this. Once the buttercream had hardened, I applied a very small amount of buttercream to my small offset spatula and smeared it on the cake. I repeated this until I had a "rustic" design that I liked.



  1. Twenty two?!?! Happy birthday to you!! So exciting - and this cake is just perfect. That buttercream!

  2. It doesnt say in the pic but it looks like you put the buttercream and the mousse between the cake layers?

    1. In the recipe it says that the mousse is put in between the cake layers and the buttercream is for masking the cake :) But you can skip the mousse and just do buttercream inside as well if you want to!

  3. Happy belated birthday!! I've never been much of a partier either and usually just opt to have a relaxing night at home on my big day :)

    Hope you had a great day at work!

    1. Thank you! I actually had a pretty good day at work and was surprised with a candle in a little cake by the head pastry chef, which was awesome!

  4. Wow! That recipe is just what I need for my weekly chocolate fix. I love the sheer magnificence in its simplicity. I'm definitely whipping up something like that within the day. Thank you so much for sharing the lovely pictures, and of course the recipe! Happy birthday, Megan! All the best to you!

    Jason Underwood @ La Patisserie

    1. Thanks so much! I hope yours tasted as good as mine!

  5. This cake looks so delicious, Megan! I love that it looks simple, yet very decadent and rich. Happy birthday! (:

    1. Thanks! Ohhh yeah, it was pretty darn decadent. But hey - you gotta treat yourself on your birthday, right?

  6. This looks incredible! I must give it a try!

  7. Amazing post. I also want to share something that monginis provide special happy birthday chocolate cake in India.

  8. Making this cake as a base cake for a modified recipe i'm making today. Following the cake recipe was trickier than I had hoped though. I converted to US system, but the measurements didn't quite make sense--66g of eggs ~about 1.5 large eggs? I also ended up with only two very thin layers of cake that I made in 8inch round pans. How did you end up with 4 layers? The 20g of cocoa (about 4tsp) was not enough to yield a dark brown cake. I had to add about 4-5x the amount of cocoa and monitored the batter for consistency. Removing the cake after 15 min at 325...the cake was still wet in the middle. I'm going to wait and see how this comes out and will bake another cake to have a recipe cake-off. We'll see what happens....

    1. I don't see why it doesn't make sense to use that amount of eggs…? Not every single recipe will use "1 egg", depending on the scale of the cake that you're making. If you measure eggs in grams, you can make any size of recipe that you want, rather than relying on the amount of eggs to dictate your recipe size.

      If you read the recipe, I baked the cake in a half sheet pan (18 x 13 x 1 in) and then cut out circular rounds from that. This means that I had one large sheet on 1 inch thick cake from which I cut four rounds from.

      The reason I use grams is because there is no "about 4 tsp", it's 20 g, no more and no less. That is the huge problem I find with using teaspoons/cups/etc. as measurements, they will never be the same measurement. You can measure 4tsp of cocoa powder and it's 20 g and then do it again and it could be 15 g or 25 g. There is huge fluctuation with using volume measurements versus weight measurements. I have made this recipe (in various sizes and in various different kitchens) many times and it has always turned out consistently.

      Please read the recipe fully before you start and follow the instructions next time. You used different measurements and different equipment and yet you expected it to be the same, which is unreasonable. I give specific instructions for a reason.

    2. I just weighed out 4 teaspoons of cocoa powder twice - the first time it was 10 g, the second time was 7 g. I'm not sure where you're getting your conversions from, but they're downright wrong. This also illustrates the inaccuracy with volume measurements. 3 grams doesn't seem like much, but it makes a big difference when making small batches and if you scale up a recipe, 3 grams of difference could become 300 grams of difference.

    3. Hi Megan,
      I just made the first two parts of the cake ie. the cake and the chocolate mousse but I have also had problems with the center being wet and the whole thing quite thin. I used the grams measurements but I just didn't get the results so I have tossed out the chocolate cake part and I may have to substitute it for another chocolate base and do the fillings using your recipe. Any suggestions or possible reasons for the failure please let me know. The only thing I can think of that may have been the issue is the baking soda. Do you interpret this as bi-carb soda or is it baking powder? The other problem I envisage is the butter milk not being acidic enough. I may actually try to replace the baking soda (bi-carb soda) with baking powder

    4. Hi Gordy,

      First of all, did you bake the cake in a half sheet pan as instructed? That is a very important part that most people don't do because it's not the normal. This create a very thin sheet of cake that bakes very quickly. It's only about 1 inch high. If you bake it in a cake ring, you'll have to increase the baking time quite a bit. And yes, baking soda is bicarbonate of soda. I don't think the buttermilk would be the problem either because I have used milk and lemon juice (10% lemon juice to milk weight) as a substitute and the cake still turned out fine.

      I can't really say what the problem is because it sounds like you did everything right! I'm sorry I couldn't be of more help!