Ingredients:
4 eggs, separated
250g/9oz caster sugar
250g/9oz plain flour
4 tsp baking powder
1 tsp vanilla essence
100ml/3½ fl oz water
100ml/3½ fl oz oil
Juice from 2 lemons

Method:
1. Preheat the oven to 175°C and line a 9 inch square tin with baking paper.
2. In a bowl beat together egg yolks and sugar, then add the rest of the ingredients except egg whites and beat until smooth.
3. Beat the egg whites until stiff and gently fold into the mixture.
4. Transfer to the prepared tin and bake for approx 45 mins or until a skewer inserted in the middle of the cake comes out clean. Leave to cool and dust with some icing sugar before serving.