Recipe :

Take cocoa powder in a bowl and mix it well with little amount of water to make a paste with no lumps. Take a pan and add water to it. Then add granulated sugar and boil it for about 2 minutes. Then add cocoa powder paste and boil it on high flame. Stir it well. Add butter and mix it well. Now add salt and vanilla essence. Mix icing sugar with some water and then add it to the mixture and boil it on medium flame. You need to continuous stir it. Switch off the gas when it becomes syrup