Blind Bake
(a) Preheat Oven to 425°F. Place crust in 9-inch pie plate.
(b) Crimp the edges decoratively or press them down with the tines of a fork. Prick the dough on the bottom all over with a fork. Place a sheet of parchment paper inside the dough and fill with pie weights. Bake for 10 minutes.
(c) Carefully remove the parchment and weights and bake until the crust is deep golden brown on the edges and lightly golden in the center

Lemon Filling (Sugar Mixture)
(a) Whisk together the granulated sugar, cornstarch and salt in a medium saucepan.
(b) Add the lemon juice and water and whisk to combine. Cook over medium-high heat, stirring frequently, until mixture comes to a boil.
(c) Cook the sugar mixture around 6 minutes or until it begins to thickening and bubbling. Once thickened, give it a whisk and reduce heat to low.

Lemon Filling (Temper the Yolk)
(a) Whisk the egg yolks together in a medium bowl or liquid measuring cup.
(b) Temper the eggs yolks by slowly adding half of the hot sugar mixture to the yolks while constantly whisking. Add the tempered yolks to the saucepan and return to the heat.
(c) Bring the mixture back to a simmer and cook, stirring constantly with a rubber spatula, for 1 minute.
(d) Remove from the heat and stir in the butter and lemon zest until completely melted and incorporated.

Crust and Filling
Pour the filling directly into the pie crust and leave on the side

Meringue (Foam)
(a) With a handheld mixer or a stand mixer fitted with a whisk attachment, beat the egg whites and cream of tartar together on medium speed for 1-2 minute until bubbles foam
(b) Add the sugar and salt, then continue beating on high speed for about 2 more minutes.

Meringue (Peaks)
(a) Place the bowl over a saucepan of simmering water, making sure the bottom of the bowl is not touching the water. Cook, whisking constantly, until the sugar is dissolved and the mixture feels hot to the touch.
(b) Transfer the bowl to the mixer and add the vanilla. Whisk on medium-high speed until stiff peaks form, 5 to 6 minutes.

Bake
Back at 425°F for 10-15 minutes or until meringue is brown.

Serve
Let pie sit at room temperature for 1 hour then chill for at least 4 hours before eating.