There are lots of good ready made pastry cases out there, I used one for quickness. But you can make it your self, look up a good, sweet short-crust pastry recipe online.

Mix the cornflour, sugar and lemon zest in a medium saucepan. Stir constantly and gradually add in the lemon juice.Cook over a medium heat, stirring constantly, until thickened and smooth

Once the mixture begins to bubbles, remove from the heat and stir in the butter until melted. Beat in the egg yolks (remember to save the whites for meringue) and a whole egg together, stir into the pan and return to a medium heat. 

Carry on mixing non-stop for a few minutes untill the mixture has thickened and will 'plop' of the spoon. Remove from the heat and set aside to cool for later.

Tip the egg whites in a bowl. Whisk to soft peaks, then gradually add half of the sugar, whisking continually.

Whisk in the cornflour, then add the rest of the sugar as before until smooth and is beginning to thicken. Quickly reheat the filling and pour it on to the pastry.

Return to the oven for 18-20 mins until the lemon filling, when touched, wobbles a tiny bit. Let the pie sit in the tin for 30 mins, then remove and leave for at least another half hour to an hour before slicing.

For the meringue recipe, refer to my early meringe recipe.

Enjoy 👍