For the crust:
For the filling:
1. In a food processor, process flour, sugar and salt. Then add cubed butter and pulse until crumbs are formed. Add egg yolk and cold water, process until dough is formed. Do not over mix.
2. Transfer the dough to a work surface, pat into a ball and flatten into a disk. Wrap in plastic and refrigerate for 1 hour. Then roll out the dough on a lightly floured board. Lightly dust the top of the dough. Roll until the dough is about 1/8 inch thick. Transfer the dough to a 9-inch (23-24cm) pie pan. evenly press the pastry onto the bottom and up the sides of your pan. Trim off the excess dough off the top of the pan. Gently pierce the bottom of the crust with a fork. Transfer to the freezer for 30 minutes.
3. Meanwhile make the filling: in a small saucepan place sugar, cornstarch, salt and mix. Stir in water and lemon juice. Cook over medium heat, stirring constantly, until mixture thickens and boils. In a medium bowl whisk egg yolks, gradually whisk in 1/2 cup of hot sugar mixture. Whisk egg yolk mixture back into the saucepan. Bring to a boil and continue to cook while stirring constantly until thick. remove from heat. Stir in butter, lemon zest. Let cool.
4. Preheat oven to 340F (170C).
5. Blind baking: line a parchment paper over the dough. Fill with dry beans, rice or pie weights. Bake for 15 min. Remove the weights and the parchment paper. Return to oven for another 10-15 minutes or until crust is slightly golden. Remove from oven. Let cool.
6. Fill the crust with the filling and place in the fridge while making the meringue.
7. Italian meringue: place sugar and water in a saucepan over high heat. Cook until sugar syrup reaches 244°F (118°C). meanwhile start to slowly whisk the egg whites in a stand mixer. When the syrup is ready, increase speed to high and with motor running, gradually pour syrup into the egg whites and whisk until becomes cool and meringue is thick and glossy (8-9 minutes).
8. Spread the meringue as you desire and brown with a kitchen torch.
• Instead of Italian meringue you can you use French meringue. But find the Italian much better for this recipe.
• If you don’t have a torch you can broil the pie at 400F (200C) until meringue is golden brown, about 10 minutes.