TRIPLE-CHOCOLATE MOUSSE CAKE

This sumptuous dessert makes a stunning finalé to a special meal.

Preparation 50 minutes, plus cooling and chilling Cooking about 1 hour 20 minutes Serves 12

FOR THE CAKE

225G DARK CHOCOLATE, CHOPPED 3 MEDIUM EGGS, SEPARATED 100G CASTER SUGAR

75G UNSALTED BUTTER, SOFTENED, PLUS EXTRA TO GREASE

FOR THE CHOCOLATE MOUSSE LAYER

150G DARK CHOCOLATE, CHOPPED 200ML DOUBLE CREAM

2 MEDIUM EGGS, SEPARATED

FOR THE WHITE CHOCOLATE MOUSSE LAYER

3 SHEETS LEAF GELATINE, SUCH AS COSTA FINE-LEAF

100G WHITE CHOCOLATE, CHOPPED 2 MEDIUM EGGS, SEPARATED

2 TSP VANILLA EXTRACT

250ML DOUBLE CREAM

FOR THE MIRROR GLAZE

15G LEAF GELATINE SHEETS (ABOUT 8) 60ML DOUBLE CREAM

60G COCOA POWDER

200G GRANULATED SUGAR

40G DARK CHOCOLATE, CHOPPED

TO DECORATE

WAITROSE COOKS HOMEBAKING BRONZE CRUNCH PIECES (OPTIONAL)

1 Preheat the oven to 180°C (160°C fan oven) gas mark 4. Grease and line a 20cm springform tin with baking parchment. Line the outside with foil to make it watertight; sit it in a large roasting tin.

2 For the cake, melt the chocolate in a heatproof bowl set over a pan of gently simmering water. Set aside to cool for 5 minutes. In a separate bowl, using a handheld electric whisk, beat the egg whites and half the sugar until fluffy. Add the rest of the sugar and continue beating until the meringue is thick and shiny.

3 Whisk the butter into the cooled chocolate, followed by the egg yolks. Stir in half the meringue mixture, then fold in the rest. Turn into the tin and smooth to level. Pour hot water into the roasting tin until it comes 2-3cm up the outside of the cake tin. Bake for 40 minutes or until a skewer put into the centre comes out clean. Cool in the tin (out of the water bath), then chill for 1 hour.

4 Remove the cake from the tin. Wash the tin. Reassemble and lightly grease the sides; line base and sides with baking parchment. Return the cake to the tin, top down.

5 To make the chocolate mousse layer, melt the chocolate as before. Set aside to cool for 10 minutes. Whip the cream to soft peaks. Whisk the yolks into the chocolate mixture. With clean beaters, whisk the egg whites to soft peaks.

6 Pour the cooled chocolate mixture into the cream and fold together. Fold in the egg whites. Turn into the prepared tin, making sure it touches the sides. Chill for 30 minutes.

7 For the white chocolate mousse layer, soak the gelatine in cold water for 5 minutes. Meanwhile, melt the chocolate as before. Take the bowl off the heat. Squeeze the excess water off the gelatine and stir into the hot chocolate to dissolve. Stir in the egg yolks and vanilla. Cool for 10 minutes.

8 Whip the cream to soft peaks. With clean beaters, whisk the egg whites to soft peaks. Fold the chocolate mixture into the cream, followed by the egg whites. Turn into the tin, level, then chill to set for about 3 hours.

9 Around 30 minutes before you want to glaze the cake, soak the gelatine in cold water for 5 minutes. Heat the cream, cocoa, sugar and 100ml water in a medium pan, whisking to dissolve. Bring to the boil, whisking, then take off the heat. Add the chocolate and whisk again.

10 Squeeze excess water from the gelatine and mix into the chocolate glaze. Strain twice through a fine sieve into a glass jug. Cool to room temperature, stirring occasionally.

11 Transfer the cake to a rack over a clean tray. Spread over the glaze, so it covers the top and drips down the sides. Decorate with Bronze Crunch Pieces if using. Chill until needed. Transfer to a cake stand to serve.