Fluffy Chocolate Mousse Cake
My chocolate brownie mousse cake has a fudgy brownie base and silky mousse topping, a rich layered dessert that’s smooth, indulgent, and irresistible.
Ingredients
Chocolate Brownie Layer
- 83 g unsalted butter cubed
- 120 g dark cooking chocolate I used 70% (see notes)
- 15 g Dutch process cocoa powder sifted (see notes)
- 2 large eggs room temperature (50-55g each)
- 105 g caster sugar superfine
- 65 g brown sugar
- 1 tsp vanilla extract
- Pinch of salt
- 50 g all-purpose flour plain flour
Chocolate Mousse Layer
- 180 g dark cooking chocolate I used 70%
- 180 g milk cooking chocolate
- 150 g heavy cream for chocolate (see notes)
- 1 pinch fine salt
- 3 large eggs 50-55g each, separated
- 5 g powdered gelatin
- 40 g cold water
- 300 g heavy cream cold, for whipping
- 1/4 tsp cream of tartar
- 7 g vanilla extract
- 50 g caster sugar
- 20 g cocoa powder to dust
- Chocolate curls to decorate
Instructions
Chocolate Brownie Layer
- Preheat your oven to 180C / 355F (fan off), 160C / 320F (fan on). Unclasp a 20cm / 8-inch springform pan. Place a piece of baking paper on bottom and place the sides on top. Clip to tighten. Set aside.
- Melt chocolate and butter - Fill a large pot a 3rd of the way with water and bring to a gentle boil. Place a heatproof glass or metal bowl on top (making sure the bottom of the bowl doesn’t touch the water). Add the chocolate and butter. Stir until melted and smooth. Alternatively, you can melt the chocolate in the microwave for 30 seconds at a time, stirring each time until smooth.
- Add cocoa powder - Turn the heat off and the sifted cocoa powder in. Use a whisk to combine until smooth. Set aside to cool to room temperature, about 10 minutes.
- Whisk eggs and sugar - To a large mixing bowl, add the eggs, both sugars, vanilla extract and salt. Use an electric hand mixer to whisk until pale, fluffy and doubled in volume, about 2-3 minutes.
- Add the chocolate mixture - Add 1/3 of the cooled chocolate mixture and whisk until well combined. Repeat with the next 1/3 until all of it has been added.
- Add dry ingredients - Add the sifted flour and fold using the spatula until no dry ingredients are showing.
- Bake - Add the mixture to the springform pan and bake for 22-24 minutes. Once baked, allow to cool completely at room temperature, about 3 hours. Carefully run a knife around the edge of the brownie to loosen from the springform pan. Clean the inside of the springform pan.
Chocolate Mousse Layer
- Add acetate - Spray the side of the pan with oil spray and place a large piece of acetate measuring 65cm (26-inches) in length and 10cm (4-inches) on the inside. The oil will help it stick to the pan. Place the cooled brownie in the pan and set aside.
- Prepare gelatin - Have a fork ready for mixing before you do this step. Add 1 tsp of powdered gelatin to a small bowl. Pour 1 tbsp of cold water on top and mix immediately until well combined.
- Melt chocolate - Add the dark and milk chocolate to a heatproof bowl over a double boiler. Stir until melted. Take off the heat.
- Heat cream and eggs - Add 150g of cream to a heatproof jug or bowl, along with the egg yolks and pinch of salt. Whisk to combine. Heat in a microwave for 20 seconds, stirring each time, until the cream feels hot to the touch. Do not overheat otherwise the yolks will begin to cook.
- Combine cream, chocolate and gelatin - Add the hot milk to the hot melted chocolate and use a whisk to combine. The mixture will look a little split. Add the gelatin mixture and stir to combine. The mixture will become smooth again. Set aside to cool until warm, not hot and not completely cool.
- Whip meringue - Add the egg whites and cream of tartar to a large clean bowl and use an electric beater to whisk until frothy, about 2 minutes on medium high speed. Then while the mixer is on high speed, begin slowly adding the sugar, 1 tbsp at a time, until it’s all been added. Continue whipping until the meringue becomes thick and glossy, about 5 minutes. Set aside.
- Whip cream - To a separate medium sized bowl, add the cold heavy cream (300g) and 1 tsp of vanilla extract. Whip using an electric hand mixer until you reach stiff peaks.
- To complete the mousse - Add the whipped cream to the cooled chocolate mixture and gently fold through using a spatula until well combined. Then add the meringue and fold through until well combined.
- Chill mousse - Pour the mixture on top of the cooled brownie layer and gently spread around using a spatula. Chill in the fridge for 5 hours. Overnight is best. The mousse needs a good amount of time to set properly.
- Dust with cocoa - dust the top of the mousse with cocoa powder before you remove it from the tin. Just a thin even layer across the top.
- To remove from the pan - Unclasped the spring form pan and take away the sides. Lift the cake up from the excess baking paper and transfer to your serving plate. Very carefully remove the baking paper by sliding underneath the brownie layer and away from the cake. Lastly, gently the mousse layer from the acetate.
- To slice - Add dark chocolate curls around the outside. Then use a large knife to slice, cleaning the knife under warm water and drying before making the next slice for nice clean cuts.
- How to get perfectly clean slices - For clean slices, run your knife under hot water, wipe dry, and slice. Repeat this process for each cut to avoid smudging the layers.
Notes
Cooking Chocolate - I used 70% Dark cooking chocolate for this recipe. It’s way less sweet than regular dark chocolate. Although dark chocolate can also be used if you prefer. Both can be found in the baking isle of your supermarket.
Dutch processed cocoa powder - is an unsweetened cocoa powder which has been treated with alkaline and potassium carbonate to neutralize the acidity that is naturally found in cocoa powder. It’s darker in color and strong in chocolate flavor.
Egg whites - I used egg whites from large eggs. Large eggs weigh 50-55g each out of the shell (yolk and whites together). Each white weigh about 30-35g each. It’s about 3 egg whites. Don’t like eating uncooked eggs? That’s ok. Use pasteurized egg whites which are gently heated. In most countries, raw egg whites are ok to consume. Just check with your country first. Immunocompromised and people who can get pregnant should stay away from raw egg whites.
Gelatin - I used platinum strength gelatin leaves. You can use gelatin powder instead. Simply mix 2 tsp of gelatin powder with 3 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.
Heavy cream – this is the type of cream you use for whipping and is also known as whipping cream. It has at least 30% fat content. Acetate - can be bought at cake stores or online. I bought mine on Amazon. Search for ‘Cake Acetate’. You want one that is at least 5 inches in height. If you don’t have acetate, you can use parchment paper in it’s place it just won’t look as smooth around the outside but will taste just as good! How to prepare a double boiler – a double boiler is a gentle way of cooking or melting ingredients. For this recipe we use it to gently cook the eggs in the mousse portion of the recipe. To prepare a double boiler fill a pot about 1/3 of the way with water and bring to a boil. Turn the heat down to low. Then place a heat proof bowl on top and proceed with the recipe. Storage - This mousse cake can be stored in an airtight container, in the fridge for up to three days. Nutrition – is an approximate and is based on per slice. A note on measurements – This recipe uses weight measurements for the most accurate results. Cup measurements can vary depending on where you are, which affects the precision needed for a recipe like this. Here is where you can learn more about how to measure ingredients using digital kitchen scales.
Heavy cream – this is the type of cream you use for whipping and is also known as whipping cream. It has at least 30% fat content. Acetate - can be bought at cake stores or online. I bought mine on Amazon. Search for ‘Cake Acetate’. You want one that is at least 5 inches in height. If you don’t have acetate, you can use parchment paper in it’s place it just won’t look as smooth around the outside but will taste just as good! How to prepare a double boiler – a double boiler is a gentle way of cooking or melting ingredients. For this recipe we use it to gently cook the eggs in the mousse portion of the recipe. To prepare a double boiler fill a pot about 1/3 of the way with water and bring to a boil. Turn the heat down to low. Then place a heat proof bowl on top and proceed with the recipe. Storage - This mousse cake can be stored in an airtight container, in the fridge for up to three days. Nutrition – is an approximate and is based on per slice. A note on measurements – This recipe uses weight measurements for the most accurate results. Cup measurements can vary depending on where you are, which affects the precision needed for a recipe like this. Here is where you can learn more about how to measure ingredients using digital kitchen scales.
Nutrition
Calories:981kcal | Carbohydrates:72g | Protein:14g | Fat:76g | Saturated Fat:46g | Polyunsaturated Fat:3g | Monounsaturated Fat:23g | Trans Fat:0.3g | Cholesterol:200mg | Sodium:66mg | Potassium:171mg | Fiber:11g | Sugar:47g | Vitamin A:1221IU | Vitamin C:0.3mg | Calcium:67mg | Iron:1mg
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