Preheat oven to 175°C then grease and line a rectangular slice tin (19cm x 29cm) with baking paper.
Beat butter, sugar, egg and vanilla in a bowl. Sift in flour, baking powder and cocoa and mix well, stir in coconut.
Spread mixture into tin and bake for approx. 20-25 minutes or until firm.
Remove from oven and spread with Rich Chocolate Icing while slice is still hot, then sprinkle with extra coconut. Allow to cool before cutting - slice should be slightly chewy.
Chelsea Chocolate Icing
Measure Chelsea Chocolate Icing into a bowl, add butter and hot water, mix well until smooth. Icing should spread easily, if it is too thick add a little more hot water to allow it to spread well.