For the pastry
- 225g plain flour
- 175g butter
- 45g icing sugar
- 1 large free-range egg, beaten
For the lemon filling
- 6 lemons, zest and juice
- 65g cornflour
- 250g caster sugar
- 6 free-range egg yolks
For the meringue topping
- 4 free-range egg whites
- 225g caster sugar
- 2 tsp cornflour
Step 1: Pre-heat the oven to 180C.
First make the pastry. Measure the flour and butter into a food processor and blend together until the mixture resembles fine breadcrumbs. Add the icing sugar, egg and one tablespoon of water and mix again until combined to a ball.
Step 2: Put the pastry out onto a worktop and roll to a 3mm thickness. Use the rolling pin to lift the pastry up and transfer it to line a 23cm/9in loose-bottomed flan tin. Make sure not to stretch the pastry. Cover this in cling film and place in the refrigerator to chill for 30 minutes.
Step 3: Remove the tin from fridge and trim off any the excess pastry. Put in your baking dish. And line the pastry with parchment. Put baking beans on top. Bake this for about 15 minutes then remove the beans and parchment and return to the oven for a further five minutes. Remove from the oven and reduce the temperature to 170C.
For the filling, mix together lemon zest and juice with cornflour and stir until you have a smooth paste. Bring 450ml of water in a pan to a boil. Put in the lemon and cornflour paste to the hot water and stir over the heat until the mixture has thickened, then remove from the heat.
In a bowl mix together the egg yolks and sugar. Now carefully whisk this into your lemon mixture in the pan. Stir this on a medium heat until thickened. Set aside for a few minutes and then pour into the baked pastry case.
For the meringue, whisk the egg whites in a free-standing mixer until soft peaks form when the whisk is removed. Add the caster sugar a little at a time, still whisking until the meringue is stiff and glossy. Add the cornflour and whisk again.
Spoon on top of the filled pastry case and spread the meringue to completely cover the lemon filling. Then create a swirl on the top of the meringue.
Bake in the oven for about 15 minutes until the filling is completely set and the meringue is lightly golden and crisp. Allow to cool completely before cutting or serve very slightly warm.