I am a huge fan of layered cakes. It is like having several cakes at once. But I won’t lie, making these is a big time commitment and it generates a lot of dishes. One day, if I ever decide to take my baking seriously, I will invest in some decent equipment to make these look nicer, but for home baking, a springform tin works fine, lined with baking paper up the edges to keep everything together. The fun part of thinking about recipes like this is the flavour combinations.
This one combines some of my favourite flavours in fruit and chocolate. It has a chocolate sponge base, that is topped with a crunchy hazelnut praline, with a layer of Nutella mousse (surprisingly light and balanced with mascarpone cheese), topped with a layer of blueberry and white chocolate mousse, which is all finally topped with some white chocolate cream. I have previously made a layered white chocolate and raspberry cake with fresh fruit, so this time I stepped it up a level to use fruit caviar, which gives the fruit punch, with a really consistent and defined shape and an even texture. The fruit caviar is folded through the blueberry white chocolate mousse and dotted over the top of the finished cake.
I’ll help with the maths here. You need nearly 600 ml cream for this! Eeep!
Nutella and blueberry chocolate mousse cake with caviar fruit
Step 1 – Chocolate sponge base
- 85 g unsalted butter
- 1¼ cups (240 g) dark chocolate (above 45% cocoa solids)
- 4 large eggs, separated
- 1 ½ tsp vanilla extract
- ½ tsp salt (or a pinch – to taste)
- 75 g packed light brown sugar, sifted
- Preheat oven to 160°C (140°C fan forced oven).
- Lightly grease and line a 23 cm springform pan with baking paper.
- Melt the butter and chocolate over a double boiler. Set aside to cool for 5 minutes.
- Using a stand mixer with a whisk attachment, whisk the egg whites and salt at medium speed until frothy.
- Slowly add the brown sugar and increase the mixer to high speed. Beat until soft peaks form.
- Whisk the vanilla extract and egg yolks into the slightly cooled chocolate mixture.
- Gently fold one third of the egg white mixture into the batter to lighten it, then fold through the rest of the egg white mixture until there are no more white streaks.
- Pour your batter into the prepared pan, making sure that it spreads out in an even layer.
- Bake for about 25 to 30 minutes, or until the centre of the cake is just set (it will be soft, but should spring back if gently pressed with your finger).
- Allow to cool inside the pan. It will rise during baking, then sink while cooling to form a more compact cake.
- Optional (if required): Remove cake from springform tin, trim surface to flatten and expose the cake insides (this will help it to meld with the mousse layer), leaving a 3 cm high cake with an exposed surface.
- Carefully return the base layer to the springform tin (re-line with baking paper if required) ready for the next layer.
Step 2 – Hazelnut praline layer
- 80 g caster sugar
- 1 tablespoon water
- 1 tablespoon glucose syrup (helps to stop crystals)
- 50 g hazelnuts, toasted and husks removed (as best as you can)
- Layer toasted hazelnuts on a sheet of baking paper on a tray.
- Place sugar, syrup and water in a pot, heat until melted, then caramelised.
- Pour over the hazelnuts.
- Allow to set, then blitz into a fine powder.
- Evenly cover the chocolate base with the praline.
Step 3 – Nutella mousse layer
- 1 sheet gelatine
- 75 g (¼ cup) Nutella
- 50 ml mascarpone cream
- 175 ml thickened cream (35% fat content)
- Soften gelatine in cold water, squeeze and place in pot on low heat to melt with the Nutella. Allow to cool slightly
- Whisk the mascarpone into the Nutella until smooth.
- In a separate bowl, whisk the cream until thick , then gently fold through the Nutella/mascarpone/gelatine mixture.
- Layer this over the hazelnut praline, smoothing until even.
- Chill for at least half an hour.
Step 4 – Blueberry compote
- 1 punnet blueberries
- 2 tablespoons caster sugar
- Heat until sugar starts to caramelise and fruit is soft.
- Pass through sieve to remove skins.
- Set aside to cool (should be a bit over ½ cup –approx 125 ml).
- Set aside 25 ml of the blueberry compote and make the fruit caviar (see instructions for fruit caviar here). Stir through a pinch of Calcium Lactate Gluconate Powder (less than ⅛ teaspoon).
Step 5 – Blueberry and white chocolate mousse layer
- 100 ml blueberry compote
- 2 gelatine leaves
- 150 ml thickened cream (35% fat content)
- 100 g white chocolate, broken into small pieces
- 50 ml cream
- ½ teaspoon vanilla bean paste
- 1 gelatine leaf
- 150 ml cream, whipped until firm
- Place 100 ml blueberry compote in pot on stove and heat on low.
- Soften gelatine leaves in cold water, squeeze and place in pot until melted.
- Pour into a heat proof bowl, cover and cool in fridge until thickened (about 30 minutes).
- Meanwhile, heat the white chocolate over a double boiler until melted.
- Heat 50 ml cream with vanilla bean paste until steaming hot.
- Soften gelatine in cold water, squeeze and place in pot with cream until melted.
- Add the vanilla-cream to the white chocolate and mix until well combined.
- Set white chocolate-vanilla cream aside to cool to room temperature.
- Remove the blueberry jelly from fridge and beat with electric mixer until frothy.
- Add 150 ml cream to the blueberry jelly and continue to whisk for 2 minutes. Set aside in fridge while finishing off the white chocolate mousse.
- Once the white chocolate mix is cooled to room temperature, fold through the 150 ml whipped cream, then set aside about 150 ml (⅔ cup) for the final layer.
- Fold the remaining white chocolate cream through the blueberry mousse and then gentle fold through the blueberry caviar.
- Spoon the blueberry and white chocolate mousse mixture over the Nutella layer and gentle spread and smooth to the edges (try to avoid breaking the caviar).
- Layer with the remainder of the white chocolate and whipped cream mixture.
- Finally, dot with left over caviar, gently pressing down.
- Refrigerate until set – at least six hours.
- Before serving, gently unmold.