- 125g (4 oz) milk chocolate
- 125g (4 oz) dark chocolate
- 290g (10 oz) butter, cubed
- 150ml (5 fl oz) strong black coffee
- 150g (5 oz) self-raising flour
- 175g (6 oz) plain flour
- 30g (1 oz) cocoa powder
- ½ tsp bicarbonate of soda
- 350g (11 oz) caster sugar
- 4 large eggs
- 40 ml (1½ fl oz) vegetable oil
- 125 ml (4 fl oz) buttermilk
- 200g (6½ oz) white chocolate
- 100 ml (3½ oz) double cream
- Heat the oven to 160°C (gas mark 2-3). Grease a large bundt or kuggelhof tin 23 cm (9 in) in diameter and dust with cocoa.
- Chop the chocolate and place in a large saucepan with 250g of the butter and coffee. Melt over a low heat, stirring occasionally until smooth. Set aside to cool. Sift the flour, cocoa powder, soda and caster sugar into a large bowl and make a well in the centre.
- Whisk together the eggs, oil and buttermilk and pour into the flour. Mix until combined, then add the chocolate mixture in two batches, stirring well after each addition until the mixture is smooth and well combined.
- Pour into a prepared tin and bake for about 1 hour. A skewer inserted into the cake should come out clean when it is cooked. Remove the cake from the oven, cover with a clean tea towel and allow to cool completely in the tin.
- When cool, remove from the tin and trim the bottom slightly so it sits flat. Pour over the icing and decorate with silver balls. Dust with icing sugar before serving.
- To make the icing, melt the white chocolate, the remaining butter and double cream in a small saucepan over a low heat, stirring occasionally until smooth. Let it cool and thicken slightly before pouring over the cake.
If you don't have a bundt tin, you can use a 23 cm (9 in) springform tin. Grease the tin well and line the base with baking paper. It may take 1 hour 20 minutes to cook.