Line 9 inch square cake tin, I used a round one though!
Put butter in a saucepan and melt slowly.
Once melted take off the heat and add coffee granules and water, stir well, then add chocolate and sugar, keep stirring until smooth. If you find chocolate not melting quite so quickly put back on heat for 30 seconds.
When smooth and all melted, pour into a bowl.
In another bowl sift both flours and cocoa, then using a hand mixer, whisk sifted flours into chocolate mixture until smooth.
Beat in the eggs and vanilla.
Pour mixture into prepared tin and bake in oven for about 1 hr 25 mins depending on your oven. It might need another 10 minutes, just keep checking with a skewer.
When ready allow to stand in tin for 10 mins before turning out onto wire rack.
When cool you can either slice in two and use jam and cream to sandwich them together or I just bought some ready made chocolate fudge icing and iced the top layer.