Preheat the oven to 180°C and line the base of a baking tin with baking paper.

Beat the eggs and gradually add the sugar, transfer to a large bowl.Sift the flour and cornflour together and then sift over the egg mixture. Combine butter and boiling water in a small bowl and gently fold into the butter mixture. Bake in the oven for 25 minutes.

 
Turn cake onto a wire rack to cool. Cut lengthways and spread jam. Replace top and cut into small squares. Sift the icing sugar and cocoa into a large bowl. Add the milk and stir to combine. Coat the lamingtons in the cocoa mixtures and then sprinkle with coconut. Finish with whipped cream.