Chocolate orange & Grand Marnier truffle cake

Method

• step 1

  Line the base and sides of a 1kg loaf tin with cling film. Squeeze the juice from the orange and mix with 3 tbsp of the Grand Marnier. Cut away the bitter white pith from inside the orange shell, then cut the peel into fine strips and boil it in a covered pan with 300ml water for 20 mins until soft. Add the sugar, then simmer uncovered for a bit longer until you have a soft, sticky peel.

• step 2

  Melt the chocolate over a pan of water, then take from the heat and beat in the butter and egg yolks, followed by the rest of the Grand Marnier.

• step 3

  Whisk the egg whites until they hold their shape, then whip the cream until softly stiff. Fold both of them into the chocolate mixture.

• step 4

  Spoon 5 large tbsp of the chocolate mixture into the tin, then dip the finger biscuits in the orange and Grand Marnier mixture one by one and arrange over the chocolate layer – don’t soak them too much or they will fall apart. Scatter over some of the sticky peel, then spoon on another 5 tbsp of the chocolate mixture.

• step 5

  Carry on layering up the biscuits and chocolate mixture until you have 4 layers of biscuit, finishing with a chocolate layer. You should only need to use half the peel. Lightly cover with cling film and freeze until ready to serve. Freeze the remaining peel separately.

• step 6

  To serve, take the cake and orange peel out of the freezer no more than 1 hr before serving and strip off the cling film. Top with whipped cream and the remaining peel, and scatter with the grated chocolate. Keep chilled until ready to eat.