1.Preheat oven to 180°C (160°C fan). Grease a deep 23cm square cake pan; line base with baking paper.
2.Beat eggs and caster sugar in a large bowl with an electric mixer for 8 minutes or until mixture is thick and creamy.
3.Triple sift flours. Whisk flour mixture into egg mixture until just combined. Pour mixture into pan.
4.Bake cake for 25 minutes or until cake is dry to the touch and edges are coming away from the sides of the pan. Stand cake in pan for 5 minutes before turning, top-side up, onto a wire rack to cool completely.
5.Combine lemon curd, sifted icing sugar, juice and the water in a large bowl until well combined. Place coconut on a large plate.
6.Cut cake into 16 squares. Use two forks to dip squares, one at a time, into lemon mixture until coated all over; toss in coconut. Place on a wire rack until firm.
Lemontons can be made a day ahead; store in an airtight container. Make strawberry lamingtons by dipping the sponge into gluten-free strawberry topping and coating in coconut tinted with pink food colouring.Note