Preheat oven 170C
Line cake tin with baking paper, Baking dish or 2 x 20cm or cup cakes
In a medium saucepan combine water, sugar, butter, cocoa and bicarb soda, stirring over medium heat until the sugar is dissolved.
Bring to the boil and then reduce the heat and simmer uncovered for 5 minutes.
Transfer the mixture into a bowl and allow to cool to room temperature, about 45 minutes.
Add the eggs one at a time, beating well after each egg.
Add sifted flour and mix until well combined and smooth.
Pour into cake tins and bake for 50 -60 minutes or until a skewer comes out clean when inserted in the centre.
Cool in the tin for 10 minutes then transfer the cake onto a wire cooling rack to cool completely.