Preheat the oven to 180°C | 400°F. Grease a 20cm x 30cm pan and line with baking paper.

Sift the all-purpose flour, cornflour and baking powder together three times. Set aside.

In a large mixing bowl, add the eggs and beat them with an electric mixer until pale in color.

Gradually add the sugar and beat until the mixture becomes thick and forms thick ribbons when the beater is lifted.

Add vanilla and beat for few seconds. Then add flour mixture and gently fold using a spatula or metal spoon.

Combine butter and boiling water in a small heatproof bowl. Fold this gently into the prepared batter.

Pour the mixture into the prepared pan. Bake for about 20-25 minutes or until sponge springs back when touched lightly in the center. Cool the cake completely.

Cut the sides from the cake and then cut them into square or rectangle pieces.

Sift the icing sugar and cocoa into a large heatproof bowl. Then add the butter and milk. Place this over a saucepan of simmering water.

Mix until icing is smooth and thick enough to coat the back of a spoon. Place desiccated coconut in a shallow bowl.

Using 2 forks, dip each cake piece in the icing. Tap the forks on the edge of the bowl to remove excess icing.

Roll the cake gently in coconut. Transfer to a wire rack and allow to set.