Dissolve the cocoa powder in the boiling water and set aside to cool.
Put the butter and sugar in the bowl. Cream for a few seconds with a hand mixer at low speed (1-2) and gently add half the egg, followed by half the flour, gently increasing the speed to a medium speed (3-4).
Add the remaining egg and flour and mix to a smooth texture.
Add the remaining ingredients and mix till smooth and velvety.
Pour the mixture into a dish, cover with foil or greaseproof paper and steam for one hour, or till a knife inserted into the cake comes out clean.