6 eggs, at room temperature
1 cup caster sugar
1 cup self-raising flour
½ cup plain flour
2 ½ cups shredded coconut
1 cup desiccated coconut
300ml tub thickened cream, whipped
4 egg yolks
1/3 cup caster sugar
¼ cup vanilla flavoured custard powder
2 cups milk
4 cups icing sugar mixture
½ cup cocoa powder
50g unsalted butter, chopped
¾ cup milk
Lightly grease two x 8-hole mini loaf pans (2/3-cup capacity). Line bases and long sides of each hole with baking paper.
To make custard, whisk yolks, sugar and custard powder in a medium saucepan until smooth. Whisk in milk. Whisk constantly over a medium heat, until boiling and thickened. Transfer to a heatproof bowl. Cover surface with plastic wrap. Refrigerate until cold.
Beat eggs in a large bowl of an electric mixer for about 7 minutes, or until thick and pale. With motor operating, gradually beat in sugar, 1 tablespoon at a time, until dissolved.
Sift flours twice onto a sheet of baking paper. Sift again over egg mixture. Add 2 tablespoons of boiling water. Gently fold with a whisk until just combined. Pour evenly into prepared pan holes (1/3 cup in each).
Cook in a moderate oven (180C) for about 20 minutes, or until golden and sponge springs back when lightly touched. Remove from oven. Stand in pans for 5 minutes. Turn out onto a wire rack to cool.
To make icing, sift sugar and cocoa into a large, heatproof bowl. Add butter and milk. Sit bowl over a pan of simmering water. Whisk until butter is melted and mixture is smooth. Remove. Stand for 15 minutes.
One at a time, dip sponges into icing, allowing excess to drip away. Roll in combined coconuts. Place on a wire rack to set.
To serve, beat custard in a bowl with a hand-held electric mixer until smooth. Cut lamingtons horizontally in half. Sandwich together with custard and whipped cream.
TIP! Custard can be made up to one day ahead. Keep refrigerated. Filled lamingtons are best served on day of being made, but can be kept in the fridge for up to one day.