Preheat oven to 350 degrees F (175 degrees C).

Grease a square baking pan.

In a large mixing bowl, cream together softened butter and sugar until light and fluffy.

Beat in vanilla extract and eggs, one at a time, mixing well after each addition.

Gradually fold in self-rising flour and milk, alternating between portions, until the batter is well combined.

Pour the batter into the prepared pan and bake for 25 minutes, or until a wooden skewer inserted into the center comes out clean.

Let the cake cool in the pan for 5 minutes, then turn it out onto a wire rack to cool completely.

Once the cake is completely cool, slice it into squares.

Sift powdered sugar into a medium mixing bowl.

In a separate bowl, combine boiling water, vanilla extract, and cocoa powder.

Add the cocoa mixture to the powdered sugar and mix until smooth.

Dip each cake square into the chocolate icing, coating all sides.

Immediately roll the iced cake squares in shredded coconut, ensuring they are fully covered.

Place the coconut-covered lamingtons on a wire rack to allow the icing to set and dry.