Italian 45 Mins Prep · 60 Mins Cook
- Preheat the oven to 180°C, gas mark 4. Grease a 23cm cake tin.
- To make the chocolate cake, place 3 eggs and 100g of sugar in the bowl of a stand mixer fitted with a whisk attachment and beat for 20 minutes, or until very light and fluffy. Sift the flour, 25g of cocoa powder and potato starch (or corn flour) together then fold into the egg mixture gently. Pour into the cake tin and bake for 30 minutes until a toothpick inserted comes out clean. Allow to cool before unmoulding. Slice the sponge in half so you have two layers.
- To make the crunchy chocolate base, roughly chop 60g of chocolate and place it in a bowl over a saucepan of gently simmering water. Add the butter and melt together. Roughly crush the cornflakes and hazelnuts then stir in the crushed cornflakes and nuts. Press the mixture into the base of a greased 25cm cake tin. Refrigerate to set.
- To make the mousse, heat the milk in a saucepan. Set aside. Separate the egg whites from the egg yolks of 2 eggs. Whisk the sugar, corn starch and egg yolks together in a bowl then gradually pour in the hot milk. Return the mixture to the saucepan and cook, whisking continuously, until thick and glossy. Divide between two bowls. Roughly chop 120g of dark chocolate and stir it into one bowl and the hazelnut paste into the other. Sprinkle the gelatine over 2 tablespoons (approx. 30ml) of water and allow to absorb. Microwave for 30 seconds until melted and then divide between the two bowls. Stir to combine. Allow to cool to room temperature. Whip the cream until soft peaks form. Divide between the two bowls and gently fold in the cream.
- To make the sugar syrup, place 200g of sugar and 200ml of water in a saucepan and heat until the sugar dissolves. Set aside.
- To assemble the cake, cut out a 25cm circle of baking paper and line the base of a 25cm cake tin as well as the sides. Place the crunchy chocolate base into the base of the cake tin. Spread half the chocolate mousse on the base, then top with one layer of sponge cake. Spoon 2-3 tablespoons of the sugar syrup on top of the sponge then add the remaining mousse. Top with the second sponge cake layer and another 2-3 tablespoons of sugar syrup. Place in the freezer while you prepare the topping.
- To make the mirror glaze, combine the 220ml of the water, 300g of sugar, fresh cream and 90g of cocoa powder in a saucepan over a medium heat. Simmer, for approx. 5 minutes, until the mixture slightly thickens. Soften the gelatine sheets in the remaining water and add to the hot glaze. Set over an ice bath and whisk until the glaze thickens and reaches 26˚C, approx. 1 minute.
- Remove the cake from the freezer. Unmould the cake and remove the paper collar. Set it on a small cake tin on top of a baking tray. Pour the glaze over, all at once, so it runs down the sides.
- Carefully place it on a serving plate and refrigerate until ready to serve.