Chocolate Raspberry Mousse Cake

When one of my close friends has his/her birthday, I don’t mind trying to push the boat out and make a gorgeous cake. After all, you could argue, it is a celebration and a showstopper cake should be the perfect ending (or complimentary part) to a fun party. In this case, I had been given some instructions, namely that the cake needed to contain raspberries. After scouring on Pinterest, the perfect platform to actually see what the cakes look like, I ended up on this recipe, which looked perfect for the occasion. The cake is made up of mousse layers (chocolate, raspberry and vanilla, respectively), held together by gelatine and resting on a brownie base. Whoa, you could say.

There are some non-negotiable aspects which you should keep in mind when making this cake. As usual, they relate to the quality of ingredients, which needs to be the best you can get. Forget that cheap chocolate you normally find in supermarkets, go for a very good brand. I normally use Green and Black’s organic range. Their white chocolate, in particular, contains real vanilla seeds and is therefore perfect for the job. Please also go for very good raspberries. They clearly play the main role in this cake and the cheap, watery stuff you find in supermarkets would just not do. If you are put off by gelatine, please allow me to say these mousse layers are creamy and moreish, not gloopy and horrible. However, if you don’t want to use gelatine, then I suggest you either increase the amount of chocolate used or freeze the whole cake.

Ingredients (for the brownie layer)

95g plain flour
80g cocoa powder
1/2 tsp salt
1/2 tsp baking powder
115g unsalted butter, at room temperature
220g golden caster sugar
2 large eggs
2 tsp vanilla extract

Ingredients (for the chocolate mousse)

200g dark chocolate (70% cocoa solids), finely chopped
415ml double cream
2 leaves of gelatine
2 tbsp water
pinch of salt

Ingredients (for the raspberry mousse)

200g fresh raspberries
255g white chocolate, finely chopped
355ml double cream
2 leaves of gelatine
2 tbsp raspberry liqueur
pinch of salt

Ingredients (for the vanilla mousse)

255g white chocolate, finely chopped
355ml double cream
2 leaves of gelatine
2 tbsp water
pinch of salt
2 tsp vanilla bean paste

Ingredients (to finish)

150g fresh raspberries
115g dark chocolate (70% cocoa solids)
120ml double cream
chocolate decorations (optional)

Method

Preheat the oven to 180°C. Grease a 20cm springform round cake tin and line the base with baking parchment.
Start with the brownie layer: in a bowl, whisk together the flour, salt, baking powder and cocoa powder until thoroughly combined. Set aside.
Melt the butter in a saucepan over medium-to-low heat. Add the sugar and stir until it melts. Don’t allow the mixture to come to a boil. Set aside to cool slightly. Once the mixture is at room temperature, add the eggs, one at a time, whisking well between each addition. Pour in the vanilla extract and fold in the dry ingredients, then scrape the brownie batter into the prepared tin and bake it for 20-25 minutes. Check the cake is cooked by inserting a toothpick in the middle – if it comes out clean or with just a few moist crumbs attached, the brownie is ready. Remove from the oven and allow to cool completely.
Once the brownie is stone cold, gently open the sides of the springform tin and line the sides with acetate – baking parchment is also OK, although acetate doesn’t tend to stick to the food and leaves a smoother finish. Ensure the acetate layer around the cake ring is at least 6-7cm, as the layers will be quite thick.
Now move on to the mousse layers, starting with the chocolate one. The procedure will be very similar for each one of them, but I will repeat the instructions just to be safe. Soak the gelatine leaves in a small bowl filled with cold water and leave there for a good 15 minutes. Pour the chocolate shards/chunks and the salt into a heatproof bowl, then bring about 180ml of the double cream to the boil in a saucepan. Remove from the heat and pour over the chocolate, stirring to ensure all of the dark chocolate melts and the mixture is smooth. Let it cool to room temperature, stirring occasionally.
Add the water to a small saucepan and place it over medium heat, then squeeze out as much water as you can from the gelatine leaves and add them to the saucepan. Ensure the gelatine melts, then pour it into the cooled chocolate mixture and mix well to combine. Whip the remaining double cream to soft peaks, then gently fold it into the chocolate mixture until smooth. Pour this mousse onto the brownie base and spread out to the sides in an even layer. Refrigerate for at least 30 minutes until completely set.
To make the raspberry mousse layer, make a quick puree by blending about 100g raspberries in a food processor. Pour them through a strainer to remove the seeds. Add this to the finely chopped white chocolate and the salt and transfer to a heatproof bowl.
Soak the gelatine leaves in a small bowl filled with cold water and leave there for a good 15 minutes. Bring about 180ml of the double cream to the boil in a saucepan. Remove from the heat and pour over the chocolate mixture, stirring to ensure all of the white chocolate melts and the mixture is smooth. Let it cool to room temperature, stirring occasionally.
Add the raspberry liqueur to a small saucepan and place it over medium heat, then squeeze out as much water as you can from the gelatine leaves and add them to the saucepan. Ensure the gelatine melts, then pour it into the cooled chocolate mixture and mix well to combine. Whip the remaining double cream to soft peaks, then gently fold it into the chocolate mixture until smooth. Scatter the remaining raspberries onto the chocolate mousse, making sure to leave about 1cm around the egde of the cake. Pour this mousse onto the chocolate mousse layer and spread out to the sides in an even layer, ensuring all of the raspberries are evenly covered. Refrigerate for at least 30 minutes until completely set.
Finally, on to the vanilla mousse layer. Soak the gelatine leaves in a small bowl filled with cold water and leave there for a good 15 minutes. Transfer the white chocolate and vanilla bean paste to an heatproof bowl. Bring about 180ml of the double cream to the boil in a saucepan. Remove from the heat and pour over the chocolate mixture, stirring to ensure all of the white chocolate melts and the mixture is smooth. Let it cool to room temperature, stirring occasionally.
Add the water to a small saucepan and place it over medium heat, then squeeze out as much water as you can from the gelatine leaves and add them to the saucepan. Ensure the gelatine melts, then pour it into the cooled chocolate mixture and mix well to combine. Whip the remaining double cream to soft peaks, then gently fold it into the chocolate mixture until smooth. Pour this mousse onto the raspberry mousse layer and spread out to the sides in an even layer. Refrigerate for at least 30 minutes until completely set.
To decorate the cake, proceed as before to make a chocolate ganache. Unmould the cake and remove the acetate, then pour the cooled ganache on top of the cake and use an offset spatula to push it to the edge and let it drop down the sides. Arrange the raspberries on top and decorate with the chocolate curls, balls, etc. If you want, dust with icing sugar and use some berry jam to make the raspberry shine. Best kept refrigerated until it’s time to serve it, but remove it from the fridge at least 10 minutes before slicing it. Enjoy!