Preheat oven to 180 degrees C. Lightly grease a 16x26cm baking pan with butter. Place the coconut and coconut sugar into a mixing bowl. Sift flour and cocoa and stir and stir into coconut and sugar.
Melt butter in a small saucepan over low heat or in a microwave safe jug in the microwave. Pour over dry ingredients. Add vanilla essence. Combine well.
Spoon mixture into prepared pan and press down evenly. Bake for 15 minutes or until cooked.
Sift icing sugar and cocoa into a small bowl. Add water and stir well. Ice slice while still hot. Cut into squares to serve with a glass of milk for the young ones and a nice cup of tea for the adults.
Coconut sugar and coconut flour can be purchased from good health shops.