For the Crust

1. Prepare and fully chill the crust. 
2. Preheat the oven to 375℉. Roll out a pie crust and fit it into a regular-depth pie plate. Trim off the extra pie crust so that there is a ½” over the rim of the pie plate. Fold under the extra crust and flute the edge however you like. Chill the crust for at least 30 minutes before blind baking.
3. Place a sheet or two of parchment paper over the chilled crust. Fill it about 3/4 of the way full with a combination of pie weights and/or dry rice or beans. Push the beans/pie weights to the edges of the pie plate. This helps hold up the edges of the crust.
4. Bake for 15 minutes, remove pie weights, poke bottom crust with a fork and then bake for another 10-20 minutes, until lightly browned. Remove from the oven and set aside.

For the Filling

1. In a small bowl whisk the egg yolk until lightened in color.
2. In a large saucepan over medium-high heat, combine the sugar, cornstarch, salt, water, lemon juice, and zest. Bring to a boil, stirring occasionally. Once at a boil and the mixture has thickened, remove from heat.
3. Very slowly add about ½ of the thickened lemon juice mixture while whisking it into the egg yolk. Whisk the warmed egg yolk mixture back into the pot with the remaining thickened liquid and bring to a boil, stirring constantly. Once big bubbles come up to the surface, continue to boil for 1 full minute while stirring.
4. Remove from heat and whisk in the butter until combined. Pour into your prebaked crust and smooth out in an even layer. Cool to room temperature. Place in the refrigerator for at least 3-4 hours or overnight, uncovered.

For the Meringue

1. Remove the pie from the fridge at least 1 hour before making the meringue to bring it up to room temperature.
2. In a small bowl combine the sugar and cornstarch for the meringue.
3. In a very clean bowl, use an electric whisk to whip the egg whites and cream of tartar until soft peaks form. Then add in the vanilla and salt, and slowly add the sugar and cornstarch mixture a tablespoon at a time while continuing to whip the egg whites at high speed. Whip until the peaks are stiff and the mixture is glossy. If you take a pinch in between your fingers, you should only feel one or two grains of sugar between your fingers.
4. Spread the meringue onto the room-temperature pie. Make sure to spread it all the way to the edge of the pie, sealing it to the crust, and then pile the rest in the middle and make lots of swirls.
5. Using a kitchen torch, lightly brown the outside of the meringue, focusing on the peaks and swirls. If you don’t have a kitchen torch, you could put it under a low broiler, watching it every second.
6. It is best to serve this pie within 2 hours after the meringue is added. Leftovers must be stored in the fridge.