23 Dec Hidden Centre White Chocolate Mousse Cake
Since it’s almost Christmas and there’s only one more week left of 2020, I think there’s plenty worth celebrating right now! And what is a celebration without a beautiful showstopper of a cake? Especially this festively fun white chocolate mousse cake… Make sure your guests are seated for the moment you cut the first slice and reveal the surprise starry centre!
I came across a hidden centre cheesecake on Taste.com.au, and loved the idea so much I decided to recreate a similar style cake. Undecided on what flavours to use I put it to my Instagram community to vote on the flavour of each element. The most-voted for elements were: a crunchy chocolate and ginger biscuit base, a creamy white chocolate mousse (with a hint of orange zest and an optional dash of booze), a browned butter cinnamon sponge centre, and a rich dark chocolate ganache. It turns out you guys really know your stuff, because the finished product is absolutely divine!
Although this is a perfect dessert for a Christmas or New Years Eve celebration, you can customise the shape of the cinnamon sponge to just about any occasion – try other cookie cutter shapes such as a heart, Christmas tree, Easter bunny, letter or number
TIP: The dessert can be mostly made ahead and frozen – simply freeze after adding the base layer, then defrost in the fridge overnight and decorate with the chocolate ganache before serving.
For the cinnamon genoise sponge:
30g salted butter
5ml cinnamon (1 tsp)
3 large eggs plus 1 large egg yolk
100g brown sugar
5ml vanilla essence (1 tsp)
For the white chocolate mousse:
225g white chocolate, finely chopped
75g castor sugar
5 large egg yolks7,5ml finely grated orange zest
7g gelatine leaves (3½ sheets)
45ml Cointreau or orange liqueur (optional)
For the chocolate ginger nut crunch:
200g Ginger Nuts
100g milk chocolate
50g salted butter
For the dark chocolate ganache:
250g dark chocolate, finely chopped
White and milk chocolate curls to decorate
- Start by making the cinnamon sponge. Melt the butter in a light coloured (eg stainless steel) saucepan over medium heat. Swirl the pan frequently until the butter is melted. Continue to heat the butter until it starts to smell toasty, and there are brown particles visible (these are the toasted milk proteins). Remove from the heat and set aside to cool to room temperature.
- Preheat the oven to 180°C. Grease and line a large, shallow baking tray (approx. 40 x 30cm) with baking paper. Sift the flour and cinnamon into a small bowl. Whisk the eggs, egg yolk, brown sugar and vanilla in a large bowl for 10 minutes until very thick and pale.
- Gently fold in the flour mixture and lastly the cooled browned butter. Fold until the ingredients are just combined, then carefully spread onto the prepared tray. Bake for 8-10 minutes, then cool for 1 minute before using a star cutter (about 4cm wide) to impress star shapes throughout the cake. It’s easier to do this while the cake is still warm, but don’t try to lift the shapes off the tray yet, you just want to impress the star shape into the cake for now. Cool the cake completely in the tin. Once cooled, carefully remove the star shapes and store in an airtight container for up to 2 days. (Any leftover cake can be toasted in the oven and used to crumble over ice cream or custard).
- To make the white chocolate mousse, whisk the cream until soft peak stage and chill in the refrigerator until needed. Melt the white chocolate in a heatproof bowl over a pan of simmering water. Set aside to cool.
- Add the egg yolks, castor sugar and orange zest to a heatproof bowl and place over the same pan of simmering water, whisking continuously until the sugar is fully dissolved- about 5 minutes. Remove from the heat, add in the liqueur if using, and use an electric or stand mixer to beat the mixture until very thick and pale, and until the bowl is at room temperature – about 10 minutes
- Meanwhile soak the gelatine sheets in cold water (enough to cover) until softened, about 10 minutes. Squeeze out any excess water then microwave in 5 second intervals until melted. Do not boil.
- Grease and line a large loaf tin with a double layer of clingfilm, leaving a large overhang for wrapping up later. Stir about a quarter of the whipped cream into the melted white chocolate, then add the whipped egg yolk mixture and fold together gently. Add a few tablespoons of this mixture to the melted gelatine, stirring to combine, then add back to the chocolate mixture. Lastly fold in the remaining whipped cream.
- Pour about half the mousse mixture into the loaf tin, then place a row of cinnamon stars down the middle of the mousse. Make sure they are packed closely together. Top with the remaining mousse mixture and smooth the top with a palette knife. Refrigerate for at least 6 hours, preferably overnight.
- Blitz the Ginger Nuts and milk chocolate in a food processor until you have mostly crumbs but also some larger bits. Melt the butter and add to food processor while still warm. Blend until the mixture starts to come together. Press the mixture into a thick layer onto the white chocolate mousse, ensuring it is level. Cover with the excess clingfilm and freeze for at least 2 hours. At this stage the cake can be frozen for up to 1 month and defrosted overnight in the fridge before the next step.
- To make the dark chocolate ganache, place the chocolate and cream into a heatproof bowl and microwave at 20 second intervals until 80% melted. Mix well until smooth and fully melted. Unwrap the clingfilm then invert the cake onto a cooling rack. Use a palette knife to spread the ganache over the top and sides of the cake, making it as even and smooth as possible. Carefully transfer to a serving platter, then decorate with chocolate curls and serve immediately!