For the cake:

225g soft unsalted butter
375g dark muscovado sugar
1 teaspoon vanilla extract
2 large eggs, beaten
100g dark chocolate, melted
200g plain flour
1 teaspoon bicarbonate of soda
250ml boiling water

For the icing:

200g icing sugar
160g unsalted butter
100g white chocolate, melted

Method:

1. Preheat the oven to 190, grease and line a 1kg loaf tin with a loaf liner.
2. Cream the butter and sugar together, then add the eggs and vanilla and beat.
3. Fold in the melted chocolate (I used 75g milk chocolate & 25g dark as HO prefers milk)
4. Mix up the flour and bicarb and add it to the mixture alternately spoon by spoon with the boiling water until you have a smooth and liquid batter.
5. Pour into the loaf tin and bake for around 30 minutes.
6. Turn down the oven to 170 and bake for another 15 minutes. Leave to cool in the tin completely before turning it out. It will dip in the middle as the cake is really squidgy inside.

For the icing, cream the butter and sieved icing sugar together until creamy and then add the melted chocolate and combine. This should be just the right amount of icing to cover the loaf.