Preheat oven 170C.
Brush 4 ramekins or a 3 cup round dish with the melted butter. Put on a lined baking tray.
Place sugar in a bowl. Sift the flour and cocoa over the sugar, and stir to combine.
In a small jug stir egg, cooled butter and milk together. Pour wet ingredients into the dry ingredients until a smooth batter forms.
Pour chocolate mixture into greased ramekins or dish and smooth the top with the back of a spoon.
With the extra sugar and cocoa, mix together, and then sprinkle over the chocolate mixture. Pour the boiled water over top.
Put onto tray and bake in oven for 40 minutes or until a cake like top forms and a skewer inserted halfway into the center comes out clean. Set aside for 5 minutes. This allows for the sauce below the cake to thicken and cool slightly before serving. Sprinkle icing sugar on top and serve with thickened cream and ice cream.