- 100g (3½oz) unsalted butter, diced and softened at room temperature
- 2 large free-range eggs, lightly beaten
- 250g (8oz) caster sugar
- 100g (3½oz) dark chocolate, melted
- 280g (9oz) self-raising flour
- 1tsp bicarbonate of soda
- Pinch of salt
- 2tbsp cocoa
- 250ml (8fl oz) milk
- 1tbsp lemon juice
- FOR THE FILLING
- Grated zest of 1 orange
- 100g (3½oz) caster sugar
- 3tbsp Grand Marnier
- 700ml (23fl oz) double cream
- Silver balls
- Heat the oven to 180°C (gas mark 4). Grease and line a 22cm (9in) round cake tin. Place the butter, eggs, sugar and melted chocolate in a large bowl. Sift in the flour, bicarbonate of soda, salt and cocoa. Combine the milk and lemon juice in a jug (it should curdle slightly) and pour into the bowl. Beat with a wooden spoon or hand-held electric beaters for 1-2 minutes or until smooth.
- Spoon the batter into the tin and bake for about 1 hour or until firm in the centre. Cool in the tin for 10 minutes, then turn out on to a wire rack to cool completely.
- To make the cream filling, mix together the orange zest and ¾ of the sugar and Grand Marnier and leave to macerate for 30 minutes. Strain through a fine sieve into a large bowl, then add 500ml (16fl oz) of the cream and whip until the mixture just holds its shape.
- Line a 1.2l (32fl oz) pudding basin with cling film. Cut the cake into 5mm-thick vertical slices and line the pudding bowl with a single layer of slices. Sprinkle the slices with Grand Marnier. Place a few tablespoons of the whipped cream on the bottom slice. Cover with a layer of cake slices and repeat twice, finishing with a layer of cake. Wrap and chill for at least 4 hours or overnight.
- To serve, turn out on to a plate. Whip the remaining cream with the remaining sugar until the mixture just holds. Spread the outside of the cake with the cream. Decorate with silver balls.
The cake can be made a day ahead of assembling the pudding.