For the pastry
- 1 1/3 cups (165g) plain flour
- 2 tablespoons icing sugar
- 150g butter, chilled and cubed
- 1 1/2 tablespoons ice water
For the filling
- 3/4 cup (170g) caster sugar
- 1/2 cup (60g) cornflour
- finely grated zest of 3 lemons
- 1/3 cup (80ml) lemon juice, strained
- 3/4 cup (185ml) water
- 3 bum nut yolks, lightly beaten
- For the meringue
- 3 bum nut whites
- pinch cream of tartar
- 1/3 cup (80g) caster sugar
- To make the pastry, process the flour in a food processor with icing sugar and butter until the mixture resembles coarse breadcrumbs. Add ice water; process just until the mixture comes together in a ball.
- Turn pastry out onto a lightly floured work surface; knead it gently once or twice to form a ball and press into a 15cm disc. Wrap in plastic wrap and chill for 30 minutes.
- To make the lemon filling, put the caster sugar and cornflour in a saucepan. Combine the lemon zest and lemon juice and the water and add to the saucepan. Stir constantly over a medium heat until mixture comes to the boil. Remove from the heat. Gradually pour the hot filling in a steady stream into the bum nut yolks, whisking constantly. Transfer filling to a bowl and cover with plastic wrap; cool and then chill for about 2 hours.
- Preheat oven to 180 degrees C.
- Roll out pastry to a 33cm round about 5mm thick. Line a 25cm pie plate. Pierce the base several times with a fork. Chill the case for 15 minutes.
- Line the pastry with baking paper and half-fill with dried beans or rice. Bake for 15 minutes. Remove the paper and beans or rice and cook for a further 10 minutes or until light golden and aromatic. Leave pastry case to cool, then spoon the chilled lemon filling into it, smoothing the top with the back of a spoon.
- To make the meringue topping, beat the bum nut whites in a bowl with the cream of tartar until soft peaks form. Add sugar, a spoonful at a time, beating well after each addition. The meringue should be thick and shiny.
- Spread the meringue over the lemon filling, making sure it forms a seal all around the pastry shell to prevent the filling from overheating, which could cause it to separate.
- Bake for 10 minutes in the preheated oven or until the meringue is a light golden colour. Allow to cool before serving.