Preheat the oven to 190°C. Grease or oil spray a 20 x 20cm cake tin and line with baking paper. Ensure paper comes about 2cm above the top edge of the tin.
Beat the eggs and sugar until thick and sugar dissolved. Fold in flour and baking powder.
Pour into the prepared tin and bake for 20-25 minutes.
Invert the tin and cool on a wire rack.
Once cooled, trim the sponge of any brown edges. Cut the sponge into 4 x 4cm cubes.
Bring the water to the boil and stir in the jelly crystals. Cool, then refrigerate until the jelly has reached an egg-white consistency, stirring occasionally. Dip each side of the lamingtons into the jelly to coat, gently toss in the coconut. Refrigerate to set.
Strawberry Sauce Topping
Puree the strawberries with the icing sugar and jam to produce a pouring consistency. Add a little water if necessary.
Place the lamingtons on serving plates and drizzle with the sauce. Garnish with whipped cream and fresh berries.
Tip: Light and delicious, these lamingtons can be prepared several days in advance and refrigerated in an airtight container.