Add the eggs, orange zest & milk, mix well.
Whisk in the flour, cocoa powder and baking powder.
Line a 12 x 9 inch pan and spoon in the cake batter, smooth over and pop in the oven for 25-30 minutes. Allow to cool.
To make the icing, mix the icing sugar, cocoa powder and water together until you have a thick gloopy consistency. Spread over the cool cake, sprinkle with Orange Zest . Decorate with Orange segments.