Preheat oven to 170°C. Put crushed biscuits into a mixing bowl. Add melted fat and mix with a wooden spoon. Firmly press mixture into base and up the side of a 9" flan dish.

For the filling, mix together lemon rind, juice and corn flour in a large bowl. Bring 450ml (¾ Pint) water to the boil in a pan. Stir enough water into corn flour mixture to make a smooth paste.

Return mixture to pan. Cook over a low heat, stirring, until thickened. Stir in caster sugar. Cool slightly, then beat in egg yolks. Pour into dish.

For the meringue, put egg whites in a spotlessly clean, dry bowl. Beat with an electric whisk until soft peaks form. Whisk in two-thirds of the caster sugar, a tablespoon at a time, whisking well after each addition. Whisk until stiff peaks form. Fold in remaining sugar and vanilla essence.

Spread meringue over lemon filling and swirl with the back of a spoon. Bake the pie for 35 - 40 minutes or until golden. Allow to cool, then chill until required.