How to Make Lemon Meringue Pie

Instructions

1. For the dough, combine the flour, sugar, and salt together. Add the oil and blend in using a pastry cutter, electric beaters, or a mixer fitted with the paddle attachment, until the flour looks evenly crumbly in texture.
2. Add the butter and cut in until rough and crumbly but small pieces of butter are still visible. Stir the water and vinegar (or lemon juice, if using) together and add all at once to the flour mixture, mixing just until the dough comes together. Shape the dough into 2 disks, wrap and chill until firm, at least an hour. The dough can be made up to 2 days ahead and stored chilled or can be frozen for up to 3 months, thawing in the fridge before rolling.
3. Roll out one disc of dough on a lightly floured work surface until it is in a circle that is just under ¼ inch (6 mm) thick. Lightly dust a 9-inch (23 cm) pie plate with flour. Press the dough into the pie plate and trim away any excess dough, pinch the edges to create a fluted pattern, and chill for at least 30 minutes, up to a day.
4. Preheat the oven to 400 °F (200 °C). Line the chilled pie shell with tin foil and fill the foil with dried beans, raw rice, or pie weights. Bake the pie shell for 20 minutes, then carefully remove the foil and weights and bake the crust for 8 to 10 minutes more, until the center of the pie shell is dry-looking and just starts to brown a little. Immediately after removing the pie shell from the oven, brush the hot crust with a little of the whisked egg white. This will create a barrier to keep the crust crispy once filled. Reduce the oven temperature to 325 °F (140 °C).
5. For the filling, whisk the sugar and cornstarch together in a medium saucepot, then whisk in the cold water. Have the other ingredients measured and nearby. Bring the sugar mixture up to a full simmer over medium-high heat, whisking as it cooks, until the mixture is thick and glossy.
6. Pour about a cup of this thickened filling into the egg yolks while whisking, then return this to the pot and whisk just one minute more. Whisk in the lemon juice and cook until the filling just returns to a simmer. Remove the pot from the heat and whisk in the butter then immediately pour the hot filling into the cooled pie shell (the filling will seem very fluid, but it will set up once chilled). Cover the surface of the filling with plastic wrap to keep it hot. Immediately prepare the meringue topping.
7. Whip the egg whites with the cream of tartar on medium speed until foamy, then increase the speed to high and gradually pour in the granulated sugar and icing sugar, and continue whipping just until the whites hold a medium peak when the beaters are lifted.
8. Remove the plastic wrap from the hot lemon filling, then dollop half of the meringue directly onto the filling (which will still be soft, so work gently). Be sure to spread the meringue so that it completely covers the lemon filling and connects with the outside crust, then use a bamboo skewer or paring knife to swirl the meringue just a touch (this will secure it to the lemon curd). Dollop the remaining meringue onto the pie and use the back of your spatula to lift up the meringue and creates spikes. Bake the pie for about 20 minutes at 325 °F (140 °C), until the meringue is nicely browned.