Within the work bowl of a meals processor, pulse flour and salt till mixed. Add chilly butter, and pulse till combination is crumbly and butter is pea-size. With processor working, add ⅓ cup (80 grams) ice water in a sluggish, regular stream simply till dough comes collectively. (Combination might seem crumbly. It needs to be moist and maintain collectively when pinched. Add extra ice water if wanted.)

Prove dough, and press right into a flat disk. Wrap tightly in plastic wrap. Refrigerate for at the very least 1 hour or as much as 2 days. Past 2 days, dough will be frozen for as much as 3 months. If utilizing dough from frozen, let thaw in fridge in a single day.

Preheat oven to 425°F (220°C).

On a calmly floured floor, roll Pie Dough right into a 12-inch circle (about ⅛-inch thickness), rotating dough as wanted to stop sticking. Gently switch to a 9-inch pie plate, urgent into backside and up sides, and trim extra dough to ½ inch past fringe of plate. Fold edges beneath, and crimp as desired. Dock backside of dough with a fork, and freeze for quarter-hour.

High dough with a chunk of parchment paper, letting ends lengthen over edges of plate. Add pie weights.

Bake till edges are golden brown, 15 to 17 minutes. Take away parchment and weights, and bake till backside of crust is dry and golden, 5 to 7 minutes extra. Let cool utterly.

In a medium saucepan, whisk collectively sugar and cornstarch. Add egg yolks and egg, and whisk vigorously till mixed. Whisk in lemon zest and juice, ⅓ cup (80 grams) water, and salt till utterly mixed and no clumps stay. Warmth over medium-low warmth, whisking continually, till combination begins to bubble and thicken, about 7 minutes; prepare dinner for two minutes. Take away from warmth, and pressure by way of a fine-mesh sieve right into a heatproof bowl. Add butter, and stir till butter is totally integrated.

Pour filling into cooled ready crust. Cowl with plastic wrap, urgent wrap straight onto floor of filling to stop a pores and skin from forming. Refrigerate till utterly cooled, at the very least 1 hour.

Take away plastic wrap from cooled filling; prime with Swiss Meringue as desired. Utilizing a handheld kitchen torch, fastidiously brown meringue as desired. Finest served similar day.

Within the prime of a double boiler, whisk collectively egg whites, sugar, salt, and cream of tartar. Cook dinner over simmering water, stirring often, till sugar dissolves and an instant-read thermometer registers 160°F (170°C), about 7 minutes.

Switch combination to the bowl of a stand mixer. Utilizing the whisk attachment, beat at excessive pace till tripled in quantity and stiff peaks type, 3 to 4 minutes. Beat in vanilla. Use instantly.