Chocolate Brownie Mousse Cake
Each slice of this Chocolate Brownie Mousse Cake is absolute heaven! It’s a two layered cake that starts with a rich and decadent brownie. Then you have a high, lighter than air chocolate mousse that melts in your mouth.
This cake isn’t for the faint of heart, it’s decadent! My perfectly light double chocolate mousse cake starts off with a chocolate brownie base that is topped with the lightest and most splendid mousse you’ve ever had. Slicing into this cake is so satisfying, eating it is simply divine!
Every wondered what eating chocolate air is like? This mousse is the answer! It’s got eggs that are perfectly whipped, paired with whipped cream and chocolate, it all comes together to create a lighter than air mousse. It’s not as airy as most other mouses, but it’s rich, perfectly set and each slice melts in your mouth.
If you’re as obsessed with chocolate desserts as I am, I have loads of recipes on the blog but my top recommendations are my Classic Chocolate Mousse, Fudgy Chocolate Brownie Pie and my Easy Chocolate Fudge Cake. All great chocolate desserts. I’ll leave a longer list at the bottom of this post!
Dreamy Chocolate Mousse in Cake Form!
I love this multi layered chocolate cake because it combines two of my favorite things. Creamy Mousse on top of a deliciously rich and fudgy brownie layer. Here’s some reasons you’ll love it!
- Light and smooth – although not as airy as most other mousse cakes, the mousse layer is ultra light and silky in every bite!
- Fudgy Brownie Layer – rich, buttery and chewy. Such a great contrast in texture to the mousse.
- Ultra-chocolate hit – this recipe uses cocoa powder and melted chocolate with a little hint of coffee to intensify the rich chocolate flavor found throughout the dessert.
Why this recipe works
A combination of gelatin and chocolate helps set this cake. It’s what helps give the mousse enough structure to stand on it’s own. The whipped eggs (gently cooked and safe to eat) combined with the whipped cream help make it light and airy!
Ingredients You Need To Make Double Chocolate Mousse Cake
Note: the whole recipe, including the ingredient quantities, can be found at the bottom of this page – just scroll down to the bottom, or click the ‘Jump to Recipe’ button at the top of this post.
- Butter – I used unsalted butter.
- Cooking chocolate – make sure you use dark cooking chocolate. This can be found in the baking isle.
- All-purpose flour – also known as plain flour.
- Cocoa powder – use Dutch processed if you can because it has a stronger chocolate flavor and is less acidic. Natural will also work.
- Salt – I used fine salt.
- Eggs – I used large eggs.
- Caster sugar – also known as superfine sugar. Granulated sugar will also work.
- Brown sugar – light or dark will work.
- Vanilla Extract – Always use good quality vanilla extract when baking, it makes a huge difference. I have a great recipe here for it if you’d like to try your own!
- Coffee shot – You can use a coffee machine to do this or just combine 2 tsp instant coffee powder with 1 tbsp boiling water.
Chocolate Mousse Layer
- Cooking Chocolate – I used dark cooking chocolate. Specifically, the Nestle cooking buttons which are designed to be easily melted and used for baking and desserts. They can be found in the baking isle of your supermarket.
- Eggs – I used large eggs. For this recipe you’ll need to separate your eggs. It’s easier to separate your eggs if they’re cold. I’ve updated the recipe method to gently cook the eggs which makes them safe to eat.
- Gelatin leaves – the gelatin leaves help the mousse set. There are different types of gelatin and different strengths. I used gelatin leaves which need to be soaked in water before being added to something warm to melt. In this case, the warm ganache for the mousse mixture. Strength wise: you’ll need a platinum strength gelatin. You can use gelatin powder instead. Simply mix 3 tbsp of gelatin powder with 6 tbsp cold water. Mix using a fork and allow to rest for 5 minutes. This is what you’ll add to your chocolate mixture and stir through until completely melted.
- Vanilla Extract – same as above.
- Caster sugar – also known as superfine sugar. Caster sugar is ideal for the mousse portion of the recipe as it melts into the meringue more easily than granulated sugar, reducing the risk of overwhipping and getting grainy mousse.
How to make Double Chocolate Mousse Cake!
For the full steps, check out the recipe card at the bottom of this post.
- Melt the butter and chocolate over a double boiler.
- Combine the dry ingredients together.
- Whip the eggs and sugar together.
- Add the coffee shot (optional)
- Mix in the cooled chocolate and butter mixture.
- Add the dry ingredients and fold through.
- Pour into a greased and lined springform pan and bake.
- Once baked, allow the brownie layer to cool completely, take out of the springform pan and line the side of the pan with acetate. More on acetate and where to buy it below.
- Soak the gelatin leaves (more on what to use instead of leaves below!)
- Melt the chocolate over a double boiler
- Mix soaked gelatin into the warm chocolate. Add the egg yolks and mix. Allow to cool.
- In a separate bowl, mix the egg whites and sugar and then stir over a double boiler until the sugar is melted.
- Allow to cool slightly before whipping until thick and glossy.
- Whip the heavy cream until you reach stiff peaks.
- Fold the meringue through the cooled (very slightly warm is ok) chocolate mixture and then fold through the cream.
- Add to the prepared tin.
- Allow to set in the fridge for 4 hours, ideally overnight before unclasping and peeling acetate away.
What happens if I don’t have Gelatin leaves?
Gelatin is one of the key things that helps this mousse set. If you don’t have them in leaf form, use gelatin powder. To use gelatin powder, simply mix 3 tbsp of gelatin powder with 6 tbsp cold water. Mix using a fork and allow to rest for 5 minutes. This is what you’ll add to your chocolate mixture and stir through until completely melted.
What if I don’t have acetate?
I used acetate to help make taking this cake out of the springform pan easier. I bought mine on Amazon. If you search for food grade acetate it will come up. Anything about 4 inches in height is ideal. If you don’t have acetate, you can make this without it! Simply pour the mousse into the springform pan, let it set and then before unclasping it, dip a towel in hot water. Wrap the towel around the springform pan and allow it to warm the sides of the pan for 60 seconds. This will gently melt the mousse against the cake pan and help it slide out instead of sticking to the cake pan.
Tips and Tricks For Recipe Success!
- Measure out using kitchen scales – measuring ingredients out by weight and not cups is the best way to get consistent results every time!
- Make sure the chocolate is warm when adding the gelatin but cooled before adding the whipped ingredients. Don’t skip any of the steps!
- Don’t skip any of the whipping! Whipping the egg whites and heavy cream are super important to helping this mousse get its air bubbles and light texture.
- For a flawless slice – Before slicing into your cake, warm your knife up under some hot running water and then dry it. Do this with every slice for a restaurant quality flawless slice!
- It’s really important that you allow adequate time to let this mousse set. I like letting it set overnight but you can give it a good 4-5 hours in a cold fridge before unclasping.
Frequently Asked Questions about This Mousse Cake!
How do I store this?
This mousse cake can be made up to 2-3 days in advance. Simply store in an airtight container in the fridge. This cake can not be frozen.
Can this recipe be made gluten free?
Yes! There is flour in the brownies. You can replace the all-purpose flour (plain flour) with gluten free flour.
Can I leave the chocolate out?
Yes! The chocolate is in the brownie layer to help intensify the chocolate flavor but can be left out completely.
What is the best chocolate to use in the mousse layer?
Dark cooking chocolate. It’s designed to be easily melted and use in baking recipes. It can be found in the baking isle of your supermarket.
If you loved this recipe, check these out!
Did you make this? Be sure to leave a review below and tag me @thescranline on Facebook and Instagram!
Chocolate Brownie Mousse Cake
- 1/3 cup (83 g) unsalted butter cut into cubes
- 1/2 cup (100 g) dark cooking chocolate (see notes)
- 1/2 cup (75 g) all-purpose flour
- 2 tbsp (16 g) Dutch process cocoa powder sifted (see notes)
- Pinch of salt
- 2 large eggs room temperature
- 1/3 cup (70 g) 70g caster sugar (superfine)
- 1/3 cup (65 g) brown sugar
- 1 tsp vanilla extract
- 1 (20 ml) coffee shot
Chocolate Mousse Layer
- 3 cups (630 g) dark cooking chocolate
- 3 large eggs separated
- 3 gelatin leaves platinum strength or above (see notes)
- 1 3/4 cups (440 ml) heavy cream cold
- 1 tsp vanilla extract
- 1/4 cup (55 g) caster sugar
Learn How To Make it! [VIDEO]
- Preheat a fan forced oven to 160C/320F (170C/340F for no fan). Line the bottom of an 20cm / 8-inch springform pan. Set aside.
- Add the chocolate to a heatproof bowl and microwave for 30 seconds at a time, stirring each time until melted. Alternatively, you can do this using a double boiler. Set aside to cool slightly.
- Add the flour, cocoa powder and salt to a small mixing bowl and use a whisk to combine.
- To a large mixing bowl, add the eggs, both sugars and vanilla extract. Use an electric hand mixer to whisk until pale, fluffy and doubled in volume, about 2-3 minutes.
- Add the coffee shot and mix until combined. Next, add the cooled chocolate mixture and whisk until well combined. Use a spatula to scrape the bowl down.
- Add the dry ingredients and fold using the spatula until no dry ingredients are showing. Add the mixture to the springform pan and bake for 15 minutes. Once baked, allow to cool completely at room temperature. Carefully run a knife around the edge of the brownie to loosen from the springform pan. Clean the inside of the springform pan. Place a piece of baking paper on bottom and place the sides on top. Clip to tighten.
- Spray the side of the pan with oil spray and place a large piece of acetate measuring 65cm (26-inches) in length on the inside. The oil will help it stick to the pan. Place the cooled brownie in the pan and set aside.
- Chocolate - Add the dark chocolate and 3/4 cup (185ml) heavy cream to a heatproof bowl over a double boiler. Stir until melted. Take off the heat and add the egg yolks, mix using a spatula until combined. Keep the double boiler set up on the stove.
- Add the gelatin leaves to cold water and allow to soak for 5 minutes. Once bloomed, take out of the water and squeeze excess water out. Add to the chocolate mixture and stir until gelatin is melted. Set aside to cool slightly.
- Whipped Cream - Add the remaining 1 cup (250ml) of heavy cream and 1 tsp of vanilla extract to a medium sized mixing bowl and whip using an electric hand mixer until you reach stiff peaks. Set aside in the fridge until ready to use.
- Swiss meringue - Add the egg whites and sugar to a large heatproof bowl and place on top of a double boiler. Whisk for 5 minutes or until the sugar has dissolved completely. You can test this by feeling it in between two fingers.
- Take off the heat and allow to cool for 10 minutes. Use an electric hand mixer to whisk until the mixture doubles in size and becomes thick and glossy.
- To complete the mousse, add half the meringue to the chocolate mixture and gently fold through using a spatula until well combined. Add the remaining meringue and the whipped cream and fold through until evenly combined.
- Pour the mixture on top of the cooled brownie layer and spread around as evenly as you can. Chill in the fridge overnight. This needs a good amount of time to set properly.
- To remove from the pan, run a knife under hot water and dry. Run it around the top of the mouse layer before loosening it from the springform pan. Carefully lift up the sides of the pan. Gently unwrap it from the acetate and slice to serve.