To the make the pastry, place the flour and butter in a medium bowl. Rub the butter into the flour until it resembles breadcrumbs. Add the egg and mix to form a dough. Place the dough between 2 sheets of baking paper and roll out until 2-4mm thick. Place rolled pastry in the fridge and chill for 30 minutes.
To make the lemon curd, place the cornflour, sugar, lemon zest and juices into a medium sized saucepan. Stir over a medium heat until the mixture is thick and smooth. Remove from the heat, add the butter and stir until well combined. Whisk the egg yolks and whole egg together, and stir into the lemon curd.
Return the saucepan to the heat and stir until the mixture is once again thick and bubbling. Cover with plastic wrap and allow to stand for 10 minutes.
While lemon curd filling is cooling, grease a 24 cm flan tin (with high sides) and line with the pastry. Set aside. Measure meringue ingredients in readiness.
Preheat oven on CircoTherm® Intensive to 180⁰C and place wire rack in shelf position 1.
Fill pastry shell with lemon curd filling and cook for 10 minutes. While pie is cooking make the meringue.
Place the egg whites into a large mixing bowl and whisk until soft peaks form. While the mixer is running, slowly add the sugar and then the cornflour. Keep whisking until the meringue is firm and stiff.
After the pie has cooked for 10 minutes spoon the meringue on top of the lemon curd, starting from the edges and working your way into the centre. Use a spatula to shape the meringue and ensure the meringue touches the pastry shell. Alternatively, pipe on the meringue for a different effect.
Reduce the oven temperature to 160⁰C. Return the pie to the oven and cook for 20 minutes. Allow to cool completely at room temperature before cutting.
