Process flour, sugar and butter until crumbly. Add egg yolk and the water; process until ingredient come together. Knead dough on a floured surface until smooth. Enclose pastry with plastic wrap; refrigerate 30 minutes.

Make pastry

Grease a 24cm round loose-based fluted flan tin. Roll pastry between sheets of baking paper until large enough to line tin. Ease pastry into tin, press into base and side; trim edge. Cover & refrigerate 30 mins.

Preheat oven to 240°c.

Place tin on an oven tray. Line pastry case with baking paper; fill with dried beans or rice. Bake 15 mins; remove paper and beans. Bake about 10 mins; cool. Turn oven off.

Meanwhile, combine cornflour and sugar in a medium saucepan; gradually stir in juice and the water until smooth. Cook, stirring, until mixture boils and thickens. Reduce heat; simmer, stirring, 1 minute. Remove from heat; stir in rind, butter and egg yolks. Cool 10 mins.

Spread filling into pie shell. Cover, refrigerate 2 hours.

Preheat oven to 240°c.

Beat egg whites in a small bowl with an electric mixer until soft peaks form; gradually add extra sugar, beating until sugar dissolves.

Roughen surface of filling with a fork before spreading with meringue mixture. Bake pie about 2 minutes or until meringue is browned lightly.