Prepare the all-butter pie crust first. Cut the cold butter into small cubes and drop it into a food processor along with the flour and salt. Pulse the butter and flour together for a few minutes, until fine crumbs form. Slowly start adding the water with the food processor running, until a dough ball forms. Remove the dough from the processor and shape it into a disk. Wrap it well with plastic wrap and refrigerate for a minimum of 1 hour or make it the day before and chill overnight.
Preheat the oven to 425F/218C. Once the dough is chilled, roll it out on a lightly floured work surface until it’s a few inches larger than your pie or tart tin. Gently transfer the dough into the pie tin and press the dough very gently into the bottom and sides, removing the excess dough. Watch my video to see how it’s done. Line the crust with parchment paper, then fill the pie with pie weights or dried beans. Blind bake the crust for about 30 minutes, or until it’s golden brown.
For the Lemon Curd:
While the pie crust is baking, prepare the lemon curd filling. This can also be done the day before. Place the eggs, egg yolks and sugar into a large mixing bowl. Whisk vigorously for 4 to 5 minutes, until the mixture is thick, pale and ribbons off the whisk. Pour this egg mixture into a medium-sized, stainless-steel saucepan and add the lemon juice. Cook the lemon curd over medium heat, stirring constantly with a rubber spatula for about 5 minutes, until the lemon curd thickens. Remove it from the heat and add the butter and vanilla, whisking until the butter is completely melted. Allow the lemon curd to cool down for at least 20 minutes before using.
Reduce the oven temperature down to 375F/190C. Pour the prepared lemon curd into the baked pie crust, spreading it evenly to the edges. Bake the pie for another 15 minutes, then remove from the oven and chill it for at least 2 hours in the refrigerator.
For the Meringue:
For the Meringue Topping: place the egg whites into a mixer bowl and whisk on high speed for a few minutes, until soft peaks form. Into a small saucepan, add the sugar and water and attach a candy thermometer to the side. Cook the sugar over medium heat, without stirring, until it reaches 240F/115C. This usually takes about 5 to 6 minutes from the time it starts to boil. Immediately, pour the hot sugar syrup in a slow and steady stream into the egg whites, with the mixer running on medium speed; avoid the whisk attachment! Watch my video recipe to see how it’s done!
Once all the sugar syrup has been added, add the cream of tartar, lemon juice and vanilla. Continue whisking the meringue on high speed for 8 to 10 minutes, until it’s cooled to room temperature and glossy peaks form. Using a spatula, add the meringue in large dollops onto the chilled lemon pie. Use a spoon to shape the meringue into a tall mountain. If desired, use a kitchen torch to caramelize/burn the meringue.
For best results, refrigerate the lemon meringue pie overnight. This will allow the lemon curd and meringue to thicken and it will be easier to serve. Use an extra-long knife for slicing.