Double Chocolate Mousse Cake

Susan, AKA Kiwicook
Susan, AKA Kiwicook

Susan, AKA Kiwicook

In her days as a recipe developer, Susan has created over 450 recipes. Her Dutch and New Zealander roots serve as a basis for her culinary inspiration.

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Double Chocolate Mousse Cake

Have you heard the phrase, ‘Death by chocolate’? I suspect it applies quite nicely to this Double Chocolate Mousse Cake, with its chocolate studded brownie base and towering mountain of melt-in-your-mouth double chocolate mousse topping.

“Make a decadent dessert”, my (normally healthy minded) sister suggested for our family dinner this weekend. As it happens, I’d just seen the recipe for this Double Chocolate Mousse Cake which fit the ‘decadent’ bill perfectly. Without hesitation (and with eyes as wide as saucers), ‘Sis’ gave it the thumbs up, though in hindsight I reckon she’s a little more appreciative of the phrase, ‘Be careful what you ask for’…

Which brings me to the recipe at hand, borrowed from Right from the start, I questioned the abnormally large amount of ingredients – 800 grams of chocolate; nearly a litre of cream, six eggs… and that’s just the mousse… But, I was reassured by the fact that the recipe stated that it served 10 people. I should have known better. I reckon it’s likely to serve more like 15-20 people, maybe more. The thing is, it’s SO rich that you really can only handle a sliver. I’m not kidding when I say my family was ‘done in’… They willed themselves to finish (God bless them), but they were ultimately forced to surrender. The spirit was willing; the body was not! Half of the cake went back into the fridge.

But… in case I’m actually turning you off from the start, let me also assure you, it WAS sublimely delicious. The mousse – the crowning glory of this dessert – was like a thick silky cream, holding its shape when cut thanks to the added gelatin. Then, of course, there’s the brownie. The recipe paired the mousse with store-bought brownie mix, but I decided to make my own gluten-free brownie instead, which provided a dense, rich and chocolatey contrast to the cloud of mousse on top. It seemed to me that one thing that was missing was something fresh to cut through all the richness… enter raspberries – the perfect partner to chocolate.

To be honest, given the size and expense of this dessert, I’m not likely to make it again, at least not in the same proportions. I’m convinced that both the brownie and mousse components could be halved and placed in a smaller 18-20 inch pan, and I reckon it would STILL serve 8-10 people. If, however, you’re after a show-stopper dessert fit for a large party of chocolate fanatics, go no further. Enjoy!

Double Chocolate Mousse Cake

Double Chocolate Mousse Cake

Warning: This Double Chocolate Mousse Cake is seriously addictive! A rich brownie base, layers of decadent chocolate mousse, and a touch of freshness… it's chocolate heaven on a plate.
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Prep Time 40 minutes
Cook Time 45 minutes
Chilling time 8 hours
Total Time 9 hours 25 minutes
Course Dessert
Cuisine French
Servings 15 slices
Calories 554 kcal


For the brownie base:

  • 500 g 17.6 oz chocolate fudge brownie packet mix (or try this gluten-free brownie – instead just halve the recipe)

For the mousse:

  • 400 g 14.1 oz dark (70%) chocolate, chopped
  • 400 g 14.1 oz milk chocolate, chopped
  • 6 eggs separated
  • 1 titanium-strength or 3 gold-strength gelatine leaf
  • 900 ml 30.4 fl oz thickened cream
  • 1/2 cup 110g caster sugar (superfine sugar)

To serve:

  • 250 g 8.8 oz raspberries
  • 300 ml 10.1 fl oz softly whipped cream


If making brownie from brownie mix:

  • Preheat oven according to brownie packet instructions. Grease a 23cm springform cake pan and line base with baking paper. Prepare brownie mix according to instructions and spread into prepared pan.
  • Bake according to instructions, removing 5 minutes before cooking time so it is slightly undercooked. Cool completely (the brownie will pull away from edge of pan).

If making your own gluten-free brownie:

  • Use the recipe here. Halve the quantity, place in cake pan, level the top, and bake for around 40-45 minutes. Remove from oven, place on wire rack, and let it cool completely.

For the mousse:

  • Place the two types of chocolate in a heatproof bowl set over a saucepan of simmering water (don’t let the bowl touch the water) and stir until melted and smooth. Cool slightly, then beat in egg yolks (this will be extremely thick and curdled looking, but don’t worry as the added cream will smooth it out again). Set aside.
  • Soak gelatine in cold water for 5 minutes to soften. Place 200ml (6.7 fl oz) of the cream in a small saucepan over low heat and bring to a simmer. Squeeze excess water from gelatine and stir into cream until melted and combined. Set aside to cool a little, then beat the cream into the chocolate mixture.
  • Whisk remaining 700ml (23.6 fl oz) cream to soft peaks in a bowl and set aside. Place egg whites in a stand mixer and whisk to soft peaks. Add sugar, 1 tablespoon at a time, and beat until sugar is dissolved (don’t over-beat or mixture will be too difficult to fold in).
  • Fold whipped cream into chocolate mixture. Then, in 2 batches, fold in egg whites (given the volume of mixture, you may need to separate it out into two bowls, as I did).


  • Lightly spray one side of the acetate sheet/s with cooking oil (to prevent the mousse from sticking to it), then line the pan with acetate with the oiled side inwards (the acetate should fit right down to the bottom of the pan, between the pan and the brownie). Make sure the acetate is at least 5cm above the top of the pan.
  • Pour the mousse mixture over brownie base (you might find that if there’s a wide gap between the pan and the brownie, the mousse mix will settle into that gap – don’t worry, it just means you won’t see much of the brownie base from the outside when its unmoulded). Level the top with an off-set spatula, and place the cake pan in the fridge to chill overnight until set.

When ready to serve:

  • Gently release the pan from around the dessert and carefully remove the acetate. If the mousse sticks a little to the acetate, simply place an off-set spatula into warm water, wipe it dry, then smooth around the cake afterwards.
  • Very carefully, remove the cake pan base and baking paper (I used a large dinner-plate sized round spatula to do this), and place cake on a serving platter. Arrange some of the raspberries on top of the cake to decorate.
  • Cut into slices (to ensure clean slices, dunk the knife in warm water, dry with a kitchen towel and cut). As the cake is rather top-heavy, I found it easier to lay each piece on its side to serve.
  • Serve remaining raspberries alongside each served slice, together with a dollop of softly whipped cream. Put any leftovers into fridge – it keeps beautifully for a further day.


Calories: 554kcalCarbohydrates: 40gProtein: 7gFat: 45gSaturated Fat: 27gPolyunsaturated Fat: 2gMonounsaturated Fat: 13gTrans Fat: 0.01gCholesterol: 138mgSodium: 48mgPotassium: 192mgFiber: 5gSugar: 32gVitamin A: 1023IUVitamin C: 5mgCalcium: 66mgIron: 1mg
Keyword Double Chocolate Mousse, Mousse Cake
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Susan, AKA Kiwicook
About The Author
Susan, also known as the Kiwi Cook, hails from Levin, New Zealand, and has a unique Kiwi-Dutch-British heritage that influenced her culinary upbringing. As an artist, tutor, writer, and editor, Susan dedicates her weekends to creating delectable dishes. Her food philosophy embraces moderation and listening to her body's needs.

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