-
Preheat the oven to 160ÂșC.
-
Using a 22cm(9in) round cake pan spray with spray and cook and line base and sides with baking paper. Extend the paper 5cm above the pan to allow for rising.
-
Combine the broken chocolate, sifted cocoa, and water in a saucepan and stir over a low heat until the chocolate has melted and smooth.
-
Pour into a mixing bowl and leave to cool for about 15 minutes.
-
Add the butter, sugar , eggs, vanilla essence, sour cream and sifted dry ingredients to the chocolate mixture and and beat on low with an electric mixer for about 3 minutes until the mixture is smooth.
-
Spread in the pan and bake for 1 3/4hours. Test the cake by inserting a skewer into the centre. If it does not come out clean then cook for a further 10 minutes.
-
Allow to cool in the pan. Only when completely cool turn out onto a wire rack.