Preheat oven to 170 degrees Celsius. Grease a 20cm (8 inch) square cake tin.
Melt butter and chocolate together in a medium saucepan over low heat, stirring occasionally. When mixture is smooth, remove from heat and stir in brown sugar and vanilla.

Add coconut and flours and mix to combine. Add egg and mix well. Press mixture into prepared pan.

Bake for 20 minutes. Remove from oven and spread with chocolate icing while slice is still hot. Sprinkle with extra coconut. Allow icing to set then cut into squares. Store in an airtight container.

Icing
Sift icing sugar and cocoa together into a small bowl Add milk and butter and mix until icing is smooth.