Step 1

Preheat the oven to 180C/160C fan-forced. Grease a 20cm square cake pan and line with baking paper, allowing it to overhang on all sides.

Step 2

Using electric beaters, beat egg yolks and icing sugar in a large bowl until pale and thick. Beat in lemon rind and juice until combined. Beat in flour until combined. Pour in butter and beat until combined. Gradually add milk and beat until well combined.

Step 3

Using electric beaters, beat egg whites in a bowl until soft peaks form. Gradually beat in caster sugar until dissolved.

Step 4

Fold a third of the egg white into the flour mixture. Repeat in two more batches until just combined (you may have a few lumps). Pour into prepared pan.

Step 5

Bake for 50-55 minutes or until the cake is set, but wobbles slightly. Set aside in the pan to cool completely. Carefully cut into slices and serve dusted with extra icing sugar.